x varies directly as y. If constant of variation `k=40` and `y=400` find x

It is given that l varies directly as m. Find the constant of proportion (k), when l is 6 then m is 18.

If x\ a n d\ y vary inversely as each other and (i) x=3\ when \ y=8,\ find \ y\ when \ x=4 (ii) x=5\ when \ y=15 ,\ find \ x\ when \ y=12 (iii) x=3,\ find \ y\ when constant of variation =900. (iv) y=35 ,\ find \ x when constant of variation \ =7.

If x\ a n d\ y vary inversely as each other and (i) x=3\ when \ y=8,\ find \ y\ when \ x=4 (ii) x=5\ when \ y=15 ,\ find \ x\ when \ y=12 (iii) x=3,\ find \ y\ when constant of variation =900. (iv) y=35 ,\ find \ x when constant of variation \ =7.

In each of the following x and y vary directly with each other . Find the constant of variable . (i) y = 3x (ii) 2x=3y (iii) 9x=y (iv) y = 2x

y varies directly as the square root of x. When x = 16, y = 24. Find the constant of variation and the equation of variation.

x varies directly as y and x varies inversely as the square of z. When y = 75 and x = 6, then z = 5. Find the value of x when y = 24 and z = 4 :

A variable is the sum of two such quantities one of which varies directly with x and the other varies directly with x^2 . If y =3 when x =1 and y=10 when x=2 , then find the relation between x and y .