Penelope and Gillian collected coins. Gillian gave 70% of her coins to Penelope. As a result, Penelope's coins increased by 10%. If Penelope had 924 coins left, find the total number of coins the two girls had at first.
| |
Comparing the change
in Gillian's coins |
Gillian |
Penelope |
| Before |
10x1 =
10 u |
|
10x7 =
70 u |
| Change |
- 7x1 =
- 7 u |
- 1x7 =
- 7 u |
+ 1x7 =
+ 7 u |
| After |
3x1 =
3 u |
|
11x7 =
77 u |
70% =
70100 =
710 10% =
10100 =
110 The number of coins that Penelope gave to Gillian is repeated. Make the number of coins that Penelope gave to Gillian the same. LCM of 1 and 7 is 7.
Number of coins that Penelope had in the end = 77 u
77 u = 924
1 u = 924 ÷ 77 = 12
Number of coins that Gillian and Penelope had at first
= 10 u + 70 u
= 80 u
= 80 x 12
= 960
Answer(s): 960
