X varies directly with Y and Z. x = 40 when y = 10 and Z = 20. find X when y = 30 and Z = 40.

Question

asked Oct 26, 2020 187k views

1 Answer

Pubudu Dodangoda · Answer 1 · 2020-10-30T03:40:05+0000

Answer:

x = 60

Explanation:

Direct variation is of the form

y= kxz

We know x =40 and y =10 and z= 20

10 = k * 40 * 20

10 = k * 800

Divide each side by 800

10/800 = k

1/80 = k

The equation becomes

y = 1/80 xz

Let y = 30 and z = 40 and find x

30 = 1/80 * x * 40

30= 40/80 x

30 = 1/2x

Multiply each side by 2

2 * 30 = 2 * 1/2 x

60 = x