Question

If y varies directly as x, and y is 6 when x is 72, what is the value of y when x is 8?

1/9
2/3
54
96

Answer 1

The answer is 2/3 (ii)

Explanation:

Here,

Case (I)

y=6 and x=72

According to the question,

y varies directly as x, so z be the ratio between them

x/y=z

z=72/8.

z=12.

Now,

Case(ii)

x=8 and y=?

We know that,

x/y=z

8/y=12

y=12/8

y=2/3

Hence y is 2/3

Answer 2

2/3

Explanation:

Y varies directly with x is given by y = kx, where k is a constant.

y = kx, 6 =72k, k =6/72 = 1/12.

so value of y when x is 8 is:

y = kx, y = 1/12 X 8 = 2/3