Question

Nifal earned 9$ for washing two cars .He recived $1 more for the second car.How much was he paid for washing each car?Which two numbers have a sum of 9$?

Answer 1

Nifal received $ 4 for washing the first car.

Nifal received $ 5 for washing the second car.

4 and 5 have a sum of 9.

Explanation:

The problem can be rewritten as follows: Find the sum of two consecutive entire numbers equal to 9. That is:

`x + y = 9`

`y = x+1`

Then, by eliminating y:

`x + (x+1) = 9`

`2\cdot x + 1 = 9`

Now, let is clear
`x`:

`2\cdot x = 8`

`x = 4`

Nifal received $ 4 for washing the first car.

The earning for the second car is: (
`x = 4`)

`y = x +1`

`y = 4 + 1`

`y = 5`

Nifal received $ 5 for washing the second car.

4 and 5 have a sum of 9.