Question

x varies directly with cube of y. when y is 2 x is 7 what will be x if y is 4

Answer 1

Answer:

x = 56

Step-by-step explanation:

x varies directly with cube of y. when y is 2 x is 7 what will be x if y is 4

x varies directly with cube of y.

=> x ∝ y³

=> x = ay³  

where a  is a constant

x = 7 when y = 2

=> 7 = a(2)³

=> 7 = 8a

=> a = 7/8

x = (7/8)y³

now y = 4 then x will be

x = (7/8)4³

=> x = 7 * 64 /8

=> x = 7 * 8

=> x = 56

Hence value of x will be 56 when y = 4