Question

X=8 y=20 find y when x=42

Answer 1

Answer

y= 105

 

Explanation

X=8

Y=20

So,

x/y = 8/20

      = 2/5

x=(2/5)y

y= (5/2)x

When x=42

y=(5/2)×42

   =105

Answer 2

In this problem, we need to use the concept of proportions. Proportion says that two ratios (or fractions) are equal. So, we have two numbers, namely:

$x=8 \ and \ y=20$

So, the given proportion is:

$\frac{x}{y}=\frac{8}{20} \\ \\ \therefore \frac{x}{y}=\frac{2}{5}$

That is, x-out-of-y is equal to 2-out-of-5

On the other hand, we know that $x=42$, so by using the previous proportion we have:

$\frac{42}{y}=\frac{2}{5} \\ \\ Isolating \ y: \\ \\ y=\frac{42 \times 5}{2} \\ \\ y=\boxed{105}$