Xuan had an equal number of starfruits and pears at first. She sold one-fifth of the pears and bought another 21 starfruits. In the end, she had thrice as many starfruits as pears. Find the number of pears she had at first.
| |
Starfruits |
Pears |
| Before |
12 u - 21 |
5 u |
| Change |
+ 21 |
- 1 u |
| After |
12 u |
4 u |
The number of starfruits and pears at first is the same.
12 u - 21 = 5 u
12 u - 5 u = 21
7 u = 21
1 u = 21 ÷ 7 = 3
Number of pears that Xuan had at first
= 5 u
= 5 x 3
= 15
Answer(s): 15
