Sarah and Irene have some muffins each. If Sarah gives Irene 19 muffins, Sarah will have
34 as many muffins as Irene. If Sarah gives Irene 16 muffins, they will have an equal number of muffins. How many muffins does Sarah have at first?
|
Case 1 |
Case 2 |
|
Sarah |
Irene |
Sarah |
Irene |
Before |
3 u + 19 |
4 u - 19 |
3.5 u + 16 |
3.5 u - 16 |
Change |
- 19 |
+ 19 |
- 16 |
+ 16 |
After |
3 u |
4 u |
3.5 u |
3.5 u |
Total number of muffins that Sarah and Irene have
= 3 u + 4 u
= 7 u
Number of muffins that Sarah and Irene each has in the end is the same.
Number of muffins that Sarah and Irene each has in the end in Case 2
= 7 u ÷ 2
= 3.5 u
Number of muffins that Sarah had at first is the same in Case 1 and Case 2.
3.5 u + 16 = 3 u + 19
3.5 u - 3 u = 19 - 16
0.5 u = 3
1 u = 3 ÷ 0.5 = 6
Number of muffins that Sarah has
= 3 u + 19
= 3 x 6 + 19
= 18 + 19
= 37
Answer(s): 37