Diana bought five times as many cookies as Fred. After Diana ate 3 cookies, she had 9 more cookies than Fred. How many cookies did they buy altogether?
| |
Diana |
Fred |
Total |
| Before |
5 u |
1 u |
6 u |
| Change |
- 3 |
|
|
| After |
5 u - 3 |
1 u |
|
The number of cookies that Fred had remains unchanged.
If Fred had another 9 cookies in the end, the number of cookies that Diana and Fred had would be the same.
5 u - 3 = 1 u + 9
5 u - 1 u = 9 + 3
4 u = 12
1 u = 12 ÷ 4 = 3
Total number of cookies
= 5 u + 1 u
= 6 u
= 6 x 3
= 18
Answer(s): 18
