Question

12(a). Given that sin y = 8/17, find the value of tan y/(1+2tan y).
(b) An amount of #300,000.00 was shared among Otobo, Ada and Adeola. Otobo received #60,000.00, Ada received 5/12 of the remainder, while the rest went to Adeola. In what ratio was the money shared?

Accepted Answer

(a) sin y = 8/17 = opp/hyp, so opp=8, hyp=17. Adjacent = √(17²−8²) = √(289−64) = √225 = 15. tan y = opp/adj = 8/15.
tan y/(1+2tan y) = (8/15)/(1+2×8/15) = (8/15)/(1+16/15) = (8/15)/(31/15) = 8/31.

(b) Total shared = #300,000. Otobo received #60,000, so the remainder = #300,000−#60,000 = #240,000. Ada received 5/12 of #240,000 = #100,000. Adeola received the rest: #240,000−#100,000 = #140,000.
Otobo : Ada : Adeola = 60,000 : 100,000 : 140,000 = 3 : 5 : 7.

WAEC Mathematics 2019 Theory — Question 14

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