Question

Y

∝
1
√
x
If
y
=
7
when
x
=
64
find,
x
when
y
=
8

Answer 1

x = 49

Explanation:

This is an inverse relationship and it implies that, an increase in the value of one variable results in a subsequent decrease in the value of another variable.

Given the mathematical expression and data;

y = 1/√x

y = 7 and x = 64

First of all, we would find the constant of proportionality, k;

y = k/√x

7 = k/√64

7 = k/8

k = 7 * 8

Constant, k = 56

Now, to find the value of x when y = 8

y = k/√x

Substituting the values, we have;

8 = 56/√x

Cross-multiplying, we have;

8 * √x = 56

√x = 56/8

√x = 7

Taking the square of both sides, we have;

(√x)² = 7²

x = 49