If y varies directly as the square root of x and y = 3 when x = 16. Calculate y when x = 64
A
12
B
6
C
3
D
5
Verified Correct Answer: B.
Step-by-Step Mathematical Solution
y ∝ \sqrtx
y = K\sqrtx
K = y/\sqrtx = 3/\sqrt16
= 3/4
y = 3/4\sqrtx
= 3/4\sqrt64 when x = 64
= 3/4 x 8/1
= 6
Source: Myschool Past Questions Archive (Record #9796)