Question

One number is 4 less than 3 times another number. If their sum is 16, find the numbers.

What equations could be used to solve the problem if x represents a number?

Answer 1

x = 3y - 4
x + y = 16

3y - 4 + y = 16
4y = 20
y = 5

x = 3(5) - 4
x = 11

Answer 2

One number is 11 and another is 5

Explanation:

One number is 4 less than 3 times another number:

If we let "one number" be x, and

"another number" be y, we can write:

`x=3y-4`

If their sum is 16:

This means if we add both the numbers, x & y, we get 16:

`x+y=16`

Now substituting equation 1 into equation 2, we can solve for y:

`x+y=16\\(3y-4)+y=16\\3y-4+y=16\\4y=16+4\\4y=20\\y=(20)/(4)=5`

Now substituting y=5 into equation 1, we can solve for x:

`x=3y-4\\x=3(5)-4\\x=15-4\\x=11`

Hence one number is 11 and another is 5