Lucy and Irene collected buttons. Lucy gave 25% of her buttons to Irene. As a result, Irene's buttons increased by 70%. If Lucy had 189 buttons left, find the total number of buttons the two girls had at first.
| |
Lucy |
Irene |
Comparing the change
in Irene's buttons |
| Before |
4x7 =
28 u |
|
10x1 =
10 u |
| Change |
- 1x7 =
- 7 u |
+ 1x7 =
+ 7 u |
+ 7x1 =
+ 7 u |
| After |
3x7 =
21 u |
|
17x1 =
17 u |
25% =
25100 =
14 70% =
70100 =
710 The number of buttons that Lucy gave to Irene is repeated. Make the number of buttons that Lucy gave to Irene the same. LCM of 1 and 7 is 7.
Number of buttons that Lucy had in the end = 21 u
21 u = 189
1 u = 189 ÷ 21 = 9
Number of buttons that Lucy and Irene had at first
= 28 u + 10 u
= 38 u
= 38 x 9
= 342
Answer(s): 342
