Fabian had an equal number of strawberry cookies, butter cookies and blueberry cookies. After he ate 41 strawberry cookies, some butter cookies and blueberry cookies, there were 80 cookies left. The number of butter cookies he ate was thrice the number of blueberry cookies he ate. The number of butter cookies left was 20 more than the number of strawberry cookies left. How many strawberry cookies were there at first?
| |
Strawberry cookies |
Butter cookies |
Blueberry cookies |
Total cookies |
| Before |
1 p + 41 |
1 p + 3 u + 20 |
1 p + 3 u + 20 |
|
| Change |
- 41 |
- 3 u |
- 1 u |
|
| After |
1 p |
1 p + 20 |
1 p + 20 + 1 u |
80 |
Number of butter cookies and strawberry cookies was equal at first.
1 p + 3 u + 20 = 1 p + 41
3 u = 41 - 20
3 u = 21
1 u = 21 ÷ 3 = 7
Total number of cookies in the end
= 1 p + 1 p + 20 + 1 p + 20 + 7
= 1 p + 1 p + 1 p + 20 + 20 + 7
= 3 p + 47
3 p + 47 = 80
3 p = 80 - 47
3 p = 33
1 p = 33 ÷ 3 = 11
Number of strawberry cookies at first
= 1 p + 41
= 11 + 41
= 52
Answer(s): 52
