Gwen bought thrice as many cookies as Warren. After Gwen ate 7 cookies, she had 9 more cookies than Warren. How many cookies did they buy altogether?
|
Gwen |
Warren |
Total |
Before |
3 u |
1 u |
4 u |
Change |
- 7 |
|
|
After |
3 u - 7 |
1 u |
|
The number of cookies that Warren had remains unchanged.
If Warren had another 9 cookies in the end, the number of cookies that Gwen and Warren had would be the same.
3 u - 7 = 1 u + 9
3 u - 1 u = 9 + 7
2 u = 16
1 u = 16 ÷ 2 = 8
Total number of cookies
= 3 u + 1 u
= 4 u
= 4 x 8
= 32
Answer(s): 32