A varies directly as (B + 18) and A = 108 when B = 36. Find the value of A when B = 68.
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Correct answer: D
Explanation
The correct answer is option 4 i.e. 172.
Given that
A ∝ (B + 18) , A = 108 when B = 36
According to the question
A = k (B + 18)
where, k is a constant
if A = 108, B = 36
Now, 108 = k (36 + 18)
k = 108/54 = 2
Thus, A = 2(B + 18)
now, B = 68
A = 2 (68 + 18) = 2 × 86 = 172