Betty and Olivia collected coins. Olivia gave 60% of her coins to Betty. As a result, Betty's coins increased by 10%. If Betty had 99 coins left, find the total number of coins the two girls had at first.
| |
Comparing the change
in Olivia's coins |
Olivia |
Betty |
| Before |
5x1 =
5 u |
|
10x3 =
30 u |
| Change |
- 3x1 =
- 3 u |
- 1x3 =
- 3 u |
+ 1x3 =
+ 3 u |
| After |
2x1 =
2 u |
|
11x3 =
33 u |
60% =
60100 =
35 10% =
10100 =
110 The number of coins that Betty gave to Olivia is repeated. Make the number of coins that Betty gave to Olivia the same. LCM of 1 and 3 is 3.
Number of coins that Betty had in the end = 33 u
33 u = 99
1 u = 99 ÷ 33 = 3
Number of coins that Olivia and Betty had at first
= 5 u + 30 u
= 35 u
= 35 x 3
= 105
Answer(s): 105
