Billy has 10% as many coins as Simon. If Billy gives away 50% of the coins and Simon gives away 25% of his coins, they will have 160 coins altogether. How many coins do the two of them have?
| |
Billy |
Simon |
Total |
Comparing Billy
and Simon at first |
1x2 =
2 u |
10x2 =
20 u |
|
| Before |
2x1 =
2 u |
4x5 =
20 u |
|
| Change |
- 1x1 =
- 1 u |
- 1x5 =
- 5 u |
|
| After |
1x1 =
1 u |
3x5 =
15 u |
160 |
10% =
10100 =
110 50% =
50100 =
12 25% =
25100 =
14 The number of coins that Billy has at first is repeated. Make the number of coins that Billy has the same. LCM of 1 and 2 is 2 u.
The number of coins that Simon has at first is repeated. Make the number of coins that Simon has the same. LCM of 10 and 4 is 20 u.
Number of coins in the end
= 1 u + 15 u
= 16 u
16 u = 160
1 u = 160 ÷ 16 = 10
Total number of coins that the two of them have
= 2 u + 20 u
= 22 u
= 22 x 10
= 220
Answer(s): 220
