Q4 of 37 Page 195

y varies directly with square root of x and y = 9 when x = 9. Let us find the value of x when y = 6.

Given: y ∝ √x

y = k√x


Acc. To given values y = 9 and x = 9,


9 = k√9


⇒ 9 = k (3)


⇒ k = 3


So, y = 3√x …(1)


Put y = 6 in (1)


⇒ 6 = 3√x


⇒ √x = 2


Square on both sides,


x = 4.


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