Mathematics 2022 Objective — Question 1
Simplify: 2 1/6 - 5 2/3 + 4 3/4
- A. 1/4
- B. 1/4
- C. 1 1/4Correct
- D. 1 3/4
Explanation
2 1/6 - 5 2/3 + 4 3/4 = (26 - 68 + 57)/12 = 15/12 = 1 1/4.
All 80 questions from the Junior Secondary Certificate Examination (JSCE) Mathematics 2022 Objective paper, with the correct answer and a full explanation for each. Free, no signup needed.
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Simplify: 2 1/6 - 5 2/3 + 4 3/4
2 1/6 - 5 2/3 + 4 3/4 = (26 - 68 + 57)/12 = 15/12 = 1 1/4.
____ is the longest chord of a circle.
The diameter passes through the centre and is the longest chord.
Factorise: 9r² - 1
Difference of two squares: (3r)² - 1² = (3r + 1)(3r - 1).
Which one of the angles can be constructed using ruler and a pair of compasses only?
105° = 90° + 15°, and 15° is built by bisecting 60° and 30°.
Write in figures: One billion, two hundred and four million, twenty four thousand and six.
1,000,000,000 + 204,000,000 + 24,006 = 1,204,024,006.
The area of a sector of a circle of radius 8cm is 45cm². Find the size of the angle subtended at the centre of the circle, correct to one decimal place. [Take π = 22/7]
45 = (θ/360) × 22/7 × 64, so θ = (45 × 360 × 7)/(22 × 64) = 80.5°.
Solve: 5(p - 5) = 2(2p - 1)
5p - 25 = 4p - 2, so p = 23.
What is the percentage increase from 240 to 400?
Increase = 160. 160/240 × 100 = 66 2/3%.
An object makes 800 revolutions in 4 mins. Find the rate in rev/min.
800 ÷ 4 = 200 rev/min.
In a Cartesian plane point (7, -4) lies within ____ quadrant.
x is positive and y is negative: 4th quadrant.
In the diagram below, find the length PC.
PQ is parallel to AB, so triangles PCQ and BCA are similar: PC/CB = CQ/CA, so PC/8 = 15/10 and PC = 12m.
Convert 10111 (base two) to base ten.
16 + 0 + 4 + 2 + 1 = 23.
The variable y is inversely proportional to variable x. If y = 0.4 when x = 2.5, find the value of the constant of proportionality.
k = xy = 2.5 × 0.4 = 1.
A ball is drawn at random from a box containing 3 red balls, 2 white balls and 5 blue balls. What is the probability of picking a red ball?
Total = 10 balls, so P(red) = 3/10.
If x = -2, y = 4 and k = 5, evaluate 4xy + 7k
4(-2)(4) + 7(5) = -32 + 35 = 3.
Simplify: 1/(3x) + 1/(4y)
LCM = 12xy: (4y + 3x)/12xy.
If 12cm on a map represents 60km, what will be the length used to represent 400km on the map?
12/60 = L/400, so L = 80cm.
Find the value of p in the ratio below: p : 5 = 48 : 40
p/5 = 48/40, so p = 6.
Find the multiplication inverse of 0.8
1/0.8 = 5/4.
A ladder 6m long leans against a wall and makes an angle of 50° with the wall. Find the distance between the wall and the foot of the ladder, correct to two decimal places. [Cos 50 = 0.6427, Tan 50 = 1.1917, Sin 50 = 0.7660]
Distance = 6 × sin 50° = 6 × 0.7660 = 4.60m.
If the bearing of P from Q is 020°, what is the bearing of Q from P?
020° + 180° = 200°.
If p varies directly as the cube of x and p = 27, x = 3, find p when x = 2.
p = kx³: 27 = 27k, so k = 1. When x = 2, p = 8.
Solve the simultaneous equation: 5x - 2y = 14 and 2x + 2y = 14
Add the equations: 7x = 28, x = 4. Then 8 + 2y = 14, y = 3.
Calculate the total surface area of a closed cylinder with base radius 3 1/2 cm and height 5cm. [Take π = 22/7]
TSA = 2πr(r + h) = 2 × 22/7 × 7/2 × 8.5 = 187cm².
The sum of the interior angles of a polygon is 1980°. How many sides has the polygon?
(n - 2) × 180 = 1980, n - 2 = 11, n = 13.
What is the co-efficient of x in (2x + 3)²?
(2x + 3)² = 4x² + 12x + 9.
The average age of 8 girls is 15 and the average age of 6 girls is 13. Find the age of the other two girls with equal age.
Total = 8 × 15 = 120. Six girls = 6 × 13 = 78. Other two = 42, so each is 21 years.
The sum of an angle at a point is ____
Angles at a point sum to 360°.
In a rectangular shape, the breadth of the perimeter can be expressed as ____
Perimeter = 2(l + b), so b = perimeter/2 - l.
Find the area of a semi-circle of radius 7cm.
½ × 22/7 × 7 × 7 = 77cm².
Expand: 3(x + 2y) + 4(2x - y)
3x + 6y + 8x - 4y = 11x + 2y.
Calculate the value of x°.
Angles on a straight line: 135° + x = 180°, so x = 45°.
A trader bought 3 dozens of sachet milk for N1,008.00 and sold each at N35.00. Calculate his profit.
3 dozens = 36. Sales = 36 × 35 = N1,260. Profit = 1,260 - 1,008 = N252.
If a die is cast, what is the probability of getting a prime number?
Primes on a die: 2, 3, 5, so P = 3/6 = 1/2.
A man is x years old and his son is y years old. What is the average age?
Average = (x + y)/2.
A cuboid measures ym by 2ym by 4ym. Find the volume of the cuboid in terms of y.
Volume = y × 2y × 4y = 8y³ m³.
Find the median age of a group of students whose ages are: 8, 6, 10, 12, 15, 12, 16, 12, 8, 14
Ordered: 6, 8, 8, 10, 12, 12, 12, 14, 15, 16. The middle two are 12 and 12, so median = 12.
____ is a circular graph.
A pie chart is circular.
Which of the following is NOT a perfect square?
k³ is not a square (odd power).
Lines XY and PQ are parallel with a transversal line CD. If <CMY = 108°, find <QND.
<CMY = <CNQ = 108° (corresponding angles). <QND = 180° - 108° = 72° (angles on a straight line).
Subtract [c - 3d - e] from the sum of [4c + d - e] and [2c - 2e]
Worked out directly the answer is 5c + 4d - 2e, which matches none of the printed options.
Which one of the angles cannot be constructed using ruler and a pair of compasses only?
Angles built from 60° and 90° by bisection/addition (15°, 22.5°, 75°) can be constructed; 35° cannot.
____ is the difference between the highest value and the lowest value in a given data.
Range = highest - lowest.
Write 5/x + 3/y as a single fraction
The symbols were unreadable in the scan; with denominators x and y, 5/x + 3/y = (5y + 3x)/xy.
Find the rate if the simple interest on 145,000.00 for ... years is $4500.00
The number of years is cut off in the scan, so this answer is a best guess.
Find the value of √(3 1/16)
3 1/16 = 49/16, so the root is 7/4 = 1 3/4.
16 out of 64 cars in a car park are Toyota Models. What is the probability that a car chosen at random is Not a Toyota Model?
Not Toyota = 48/64 = 3/4.
Solve the simultaneous equations: x = y + 1 and x + 2y = 7
(y + 1) + 2y = 7, so 3y = 6, y = 2 and x = 3.
If p = 2, q = -3 and r = 4, calculate (25r + 12q)/(pr)²
(100 - 36)/(8)² = 64/64 = 1.
Each face of a cuboid is in the shape of a ____
A cuboid has rectangular faces.
Calculate the value of 37° 45' 1" + 34° 34' 1"
Add: 71° 79' 2"; 79' = 1° 19', so 72° 19'.
Find the reciprocal of 0.25
1/0.25 = 4.
Find the smallest number by which 108 must be multiplied to get a perfect square.
108 = 2² × 3³. Multiply by 3 to get 2² × 3⁴ = 324 = 18².
Solve: ac/(3c + 5a) ... (the equation is not clear in the scan)
The question is not legible in the scan; this answer is a guess.
Which of the following is NOT a solid figure?
A rectangle is a plane (flat) figure.
Find the square root of 3136 in index form
3136 = 2⁶ × 7², so the square root = 2³ × 7 (=56).
Calculate the perpendicular height of a cone with a radius 8cm and slant height 10cm.
h = √(10² - 8²) = √36 = 6cm.
Two angles of a right angled triangle are (x + 2)° and (2x + 4)°. Find x.
x + 2 + 2x + 4 = 90, so 3x = 84, x = 28.
If p varies inversely as the square of q and p = 3, when q = 4, what is the value of p when q = 8?
p = k/q²: k = 3 × 16 = 48. When q = 8, p = 48/64 = 3/4.
If angle A measures (20 - 5x)°, the complementary angle to A measures ____
90 - (20 - 5x) = 70 + 5x.
Given that P = 4 - 9x² and Q = 2 + 3x, what is P + Q?
P + Q = 6 + 3x - 9x² = 3(2 + 3x)(1 - x) = (6 + 9x)(1 - x).
What value of k will x² + 8x + k give a perfect square?
k = (8/2)² = 16.
The letters of GEOGRAPHY are cut and then put in a container. What is the probability of picking a letter G.
GEOGRAPHY has 9 letters, with G appearing twice, so 2/9.
Find the product of mode and median of the set: 8, 3, 1, 7, 3, 4, 8, 3, 4, 9, 5
Ordered: 1, 3, 3, 3, 4, 4, 5, 7, 8, 8, 9. Mode = 3, median = 4, product = 12.
What is the sum of the angle in an octagon?
(8 - 2) × 180° = 1080°.
Two-fifth of the students in a mixed school are boys. If there are 48 girls in the school, how many are boys?
Girls = 3/5 = 48, total = 80, boys = 2/5 × 80 = 32.
A ____ is a quadrilateral which has only one diagonal as a line of symmetry.
A kite has one line of symmetry along a diagonal.
Calculate <WZX.
Exterior angle at X (142°) = <W + <Z, so <Z = 142° - 132° = 10°.
Find the L.C.M of 2 × 3 × 5², 2² × 3 × 5 and 2 × 3 × 5
Highest powers: 2², 3¹, 5², giving 2² × 3 × 5².
If (a - 2) is a factor of 3a² - 10a + 8, find the other factor.
3a² - 10a + 8 = (a - 2)(3a - 4).
What does the digit 9 stand for in 159.087?
9 is in the units place.
The ratio of the lengths of two similar rectangles is 3 : 4. What is the ratio of their areas?
Areas are in the ratio of squares: 9 : 16.
Find the product of 1110 (base two) and 101 (base two)
14 × 5 = 70 = 1000110 in base two.
Make x the subject of the relation: 7y - x = 5 - 5x
4x = 5 - 7y, so x = (5 - 7y)/4.
A pair of lines which do not intersect at any point are called
Parallel lines never meet.
The mean age of five students whose ages are 8, x, 13, 12 and 10 is 10. Calculate the value of x in years.
(8 + x + 13 + 12 + 10)/5 = 10, so 43 + x = 50 and x = 7.
The area of a triangle is 90cm² with height 15cm. Find the base of the triangle.
½ × b × 15 = 90, so b = 12cm.
Evaluate: 11011 (base two) - [ ] (base two) = 10101 (base two). Find the box.
27 - 21 = 6 = 110 in base two.
The pie chart below shows the favourite fruits of a group of 150 students. How many students take mango?
Mango sector is about 84°, so 84/360 × 150 = 35.
The pie chart below shows the favourite fruits of a group of 150 students. What is the percentage of the students that take apple?
Apple sector is 72°, so 72/360 × 100 = 20%.
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