Dana and Emily have some shortbreads each. If Dana gives Emily 31 shortbreads, Dana will have
34 as many shortbreads as Emily. If Dana gives Emily 9 shortbreads, they will have an equal number of shortbreads. How many shortbreads does Emily have at first?
|
Case 1 |
Case 2 |
|
Dana |
Emily |
Dana |
Emily |
Before |
3 u + 31 |
4 u - 31 |
3.5 u + 9 |
3.5 u - 9 |
Change |
- 31 |
+ 31 |
- 9 |
+ 9 |
After |
3 u |
4 u |
3.5 u |
3.5 u |
Total number of shortbreads that Dana and Emily have
= 3 u + 4 u
= 7 u
Number of shortbreads that Dana and Emily each has in the end is the same.
Number of shortbreads that Dana and Emily each has in the end in Case 2
= 7 u ÷ 2
= 3.5 u
Number of shortbreads that Dana had at first is the same in Case 1 and Case 2.
3.5 u + 9 = 3 u + 31
3.5 u - 3 u = 31 - 9
0.5 u = 22
1 u = 22 ÷ 0.5 = 44
Number of shortbreads that Emily has
= 4 u - 31
= 4 x 44 - 31
= 176 - 31
= 145
Answer(s): 145