Jean has a bag containing some silver and gold coins. If she removes 10 silver coins, 40% of the coins in the bag are gold. If she adds another 50 gold coins, 60% of the coins in the bag are gold. How many silver coins are in the bag?
| |
Silver coins |
Gold coins |
| Before |
6 u + 10 |
4 u |
| Change 1 |
- 10 |
|
| After 1 |
3x2 =
6 u |
2x2 =
4 u |
| Change 2 |
|
+ 50 |
| After 2 |
2x3 =
6 u |
3x3 =
9 u |
40% =
40100 =
2560% =
60100 =
35The number of silver coins remains unchanged at the second change when she adds another 50 gold coins. Make the number of silver coins the same at the second change. LCM of 3 and 2 is 6.
Number of gold coins added
= 9 u - 4 u
= 5 u
5 u = 50
1 u = 50 ÷ 5 = 10
Number of silver coins at first
= 6 u + 10
= 6 x 10 + 10
= 60 + 10
= 70
Answer(s): 70
