Question

4. X varies directly with the square of y, where x>0,

and y >0. If x= 3 when y = 5, then what is the value
ofy when x= 48?

Answer 1

The value of y, when x = 48 is y = 12/5

Explanation:

The given parameters are;

x is directly proportional to y

Where x > 0, y > 0

For x = 3. y = 5

Therefore, we have;

x ∝ a·y²

For ,x = 3, when y = 5, we have;

3 = a × 5² = 25·a

∴ a = 25/3

When x = 48, we have;

48 = 25/3×y²

y² = 3/25 × 48 = 144/25

y = √(144/25) = 12/5

y = 12/5

The value of y, when x = 48 is y = 12/5.