Dana bought five times as many cookies as Andy. After Dana ate 7 cookies, she had 9 more cookies than Andy. How many cookies did they buy altogether?
| |
Dana |
Andy |
Total |
| Before |
5 u |
1 u |
6 u |
| Change |
- 7 |
|
|
| After |
5 u - 7 |
1 u |
|
The number of cookies that Andy had remains unchanged.
If Andy had another 9 cookies in the end, the number of cookies that Dana and Andy had would be the same.
5 u - 7 = 1 u + 9
5 u - 1 u = 9 + 7
4 u = 16
1 u = 16 ÷ 4 = 4
Total number of cookies
= 5 u + 1 u
= 6 u
= 6 x 4
= 24
Answer(s): 24
