Question

The sum of two numbers is 45 and their ratio is 7:8.find the numbers

Answer 1

Let the numbers be 7x & 8x

so by the condition given in your question we get equation

7x + 8x = 45

15x = 45

x = 3

so your required numbers are 21 & 24

Answer 2

Hello...

$x \div 45 - x = 7 \div 8$
$8x = 7(45 - x)$
$8x = 315 - 7x$
$8x + 7x = 315$
$15x = 315$
$x = 315 \div 15$
$x = 21$
$other \: number \: is \: 45 - 21 = 24$
$answer \: 21 \: and \: 24$