Yoko and Barbara collected coins. Yoko gave 20% of her coins to Barbara. As a result, Barbara's coins increased by 70%. If Yoko had 56 coins left, find the total number of coins the two girls had at first.
| |
Yoko |
Barbara |
Comparing the change
in Barbara's coins |
| Before |
5x7 =
35 u |
|
10x1 =
10 u |
| Change |
- 1x7 =
- 7 u |
+ 1x7 =
+ 7 u |
+ 7x1 =
+ 7 u |
| After |
4x7 =
28 u |
|
17x1 =
17 u |
20% =
20100 =
15 70% =
70100 =
710 The number of coins that Yoko gave to Barbara is repeated. Make the number of coins that Yoko gave to Barbara the same. LCM of 1 and 7 is 7.
Number of coins that Yoko had in the end = 28 u
28 u = 56
1 u = 56 ÷ 28 = 2
Number of coins that Yoko and Barbara had at first
= 35 u + 10 u
= 45 u
= 45 x 2
= 90
Answer(s): 90
