Ian has 70% as many erasers as Liam. If Ian gives away 20% of the erasers and Liam gives away 60% of his erasers, they will have 432 erasers altogether. How many erasers do the two of them have?
| |
Ian |
Liam |
Total |
Comparing Ian
and Liam at first |
7x5 =
35 u |
10x5 =
50 u |
|
| Before |
5x7 =
35 u |
5x10 =
50 u |
|
| Change |
- 1x7 =
- 7 u |
- 3x10 =
- 30 u |
|
| After |
4x7 =
28 u |
2x10 =
20 u |
432 |
70% =
70100 =
710 20% =
20100 =
15 60% =
60100 =
35 The number of erasers that Ian has at first is repeated. Make the number of erasers that Ian has the same. LCM of 7 and 5 is 35 u.
The number of erasers that Liam has at first is repeated. Make the number of erasers that Liam has the same. LCM of 10 and 5 is 50 u.
Number of erasers in the end
= 28 u + 20 u
= 48 u
48 u = 432
1 u = 432 ÷ 48 = 9
Total number of erasers that the two of them have
= 35 u + 50 u
= 85 u
= 85 x 9
= 765
Answer(s): 765
