JAMB Mathematics 2021 Objective — Question 8
Question 8 of 40 from the Joint Admissions and Matriculation Board (JAMB) Mathematics 2021 Objective paper, with the correct answer and a full explanation.
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8. Find a two-digit number such that three times the tens digit is 2 less than twice the units digit and twice the number is 20 greater than the number obtained by reversing the digits (a) 36 (b) 63 (c) 47 (d) 74
- A. 36
- B. 63
- C. 47Correct
- D. 74
Explanation
Let the number be AB = 10A+B. From the conditions: 3A = 2B - 2, and 2(10A+B) = 10B+A+20. Solving these simultaneously gives A=4, B=7, so the number is 47.
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