81
27
19
127
181
Correct answer is A
x∝1y
x=ky
y∝t2
y=ct2
k and c are constants.
x=kct2
Let kc=d (a constant)
x=dt2
1=d32⟹d=9
∴
x = 9 \div (\frac{1}{3})^{2}
= 9 \div \frac{1}{9} = 9 \times 9 = 81
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