Warren has 10% as many coins as Tim. If Warren gives away 50% of the coins and Tim gives away 70% of his coins, they will have 28 coins altogether. How many coins do the two of them have?
| |
Warren |
Tim |
Total |
Comparing Warren
and Tim at first |
1x2 =
2 u |
10x2 =
20 u |
|
| Before |
2x1 =
2 u |
10x2 =
20 u |
|
| Change |
- 1x1 =
- 1 u |
- 7x2 =
- 14 u |
|
| After |
1x1 =
1 u |
3x2 =
6 u |
28 |
10% =
10100 =
110 50% =
50100 =
12 70% =
70100 =
710 The number of coins that Warren has at first is repeated. Make the number of coins that Warren has the same. LCM of 1 and 2 is 2 u.
The number of coins that Tim has at first is repeated. Make the number of coins that Tim has the same. LCM of 10 and 10 is 20 u.
Number of coins in the end
= 1 u + 6 u
= 7 u
7 u = 28
1 u = 28 ÷ 7 = 4
Total number of coins that the two of them have
= 2 u + 20 u
= 22 u
= 22 x 4
= 88
Answer(s): 88
