Question

Suppose y varies directly with x, and y=25 when x=140. what is the value of y when x=36

Answer 1

`\displaystyle y=(45)/(7)`

Explanation:

Direct Proportions

A direct proportion is a relation between variables where their ratio is a constant value. This means that if y and x are proportional, then:

`\displaystyle (y)/(x)=k`

Where k is a constant.

We know y=25 when x=140, and it's required to find the value of when x=36.

For any pair of values (x,y), their ratio is constant:

`\displaystyle (25)/(140)=(y)/(36)`

Multiplying by 36:

`\displaystyle y=36*(25)/(140)`

`\displaystyle y=(900)/(140)`

Simplifying:

`\mathbf{\displaystyle y=(45)/(7)}`