Question

So I don't really understand how to solve this.. Here's the question.

The Perez family arrived at Tia Elena's house with 6 gallons of gas. Along the way, they first used 8 gallons and then added 10 gallons; then used 5 gallons. How many gallons of gas did the Perez family start with? Work backward, then solve.

Here are the possible answers:

A) 3 Gallons
B)7 Gallons
C)9 Gallons
D)11 Gallons

Answer 1

First lets see what information they give us.
We know that they arrived with 6 gallons of gas and along the way they pumped 18 gallons and used 5.
(i got 18 by adding 8 and 10 just to make it simpler)

Answer 2

The answer is 9 gallons.

? - 8 + 10 -5 = 6
Then fill in the choices.

3-8+10-5=0
7-8+10-5=4
9-8+10-5=6
11-8+10-5=8