Zoe and Sabrina have some tarts each. If Zoe gives Sabrina 21 tarts, Zoe will have
14 as many tarts as Sabrina. If Zoe gives Sabrina 11 tarts, they will have an equal number of tarts. How many tarts does Zoe have at first?
| |
Case 1 |
Case 2 |
| |
Zoe |
Sabrina |
Zoe |
Sabrina |
| Before |
1 u + 21 |
4 u - 21 |
2.5 u + 11 |
2.5 u - 11 |
| Change |
- 21 |
+ 21 |
- 11 |
+ 11 |
| After |
1 u |
4 u |
2.5 u |
2.5 u |
Total number of tarts that Zoe and Sabrina have
= 1 u + 4 u
= 5 u
Number of tarts that Zoe and Sabrina each has in the end is the same.
Number of tarts that Zoe and Sabrina each has in the end in Case 2
= 5 u ÷ 2
= 2.5 u
Number of tarts that Zoe had at first is the same in Case 1 and Case 2.
2.5 u + 11 = 1 u + 21
2.5 u - 1 u = 21 - 11
0.5 u = 10
1 u = 10 ÷ 0.5 = 20
Number of tarts that Zoe has
= 1 u + 21
= 1 x 20 + 21
= 20 + 21
= 41
Answer(s): 41
