David had some pastries.
37 of them were cupcakes. The rest were croissants. He sold
25 of the cupcakes and 7 croissants. In the end, he had 80 pastries left. How many pastries did he sell?
| |
Cupcakes |
Croissants |
Comparing pastries
at first |
3x5 =
15 u |
4x5 =
20 u |
Before
|
5x3 =
15 u |
20 u |
Change
|
- 2x3 =
- 6 u |
- 7 |
After
|
3x3 =
9 u |
20 u - 7 |
The number of cupcakes at first is repeated. Make the number of cupcakes at first the same. LCM of 3 and 5 is 15.
Total number of pastries left
= 9 u + 20 u - 7
= 29 u - 7
29 u - 7 = 80
29 u = 80 + 7
29 u = 87
1 u = 87 ÷ 29 = 3
Number of pastries that David sold
= 6 u + 7
= 6 x 3 + 7
= 18 + 7
= 25
Answer(s): 25
