Owen has 90% as many erasers as Tim. If Owen gives away 50% of the erasers and Tim gives away 30% of his erasers, they will have 230 erasers altogether. How many erasers do the two of them have?
| |
Owen |
Tim |
Total |
Comparing Owen
and Tim at first |
9x2 =
18 u |
10x2 =
20 u |
|
| Before |
2x9 =
18 u |
10x2 =
20 u |
|
| Change |
- 1x9 =
- 9 u |
- 3x2 =
- 6 u |
|
| After |
1x9 =
9 u |
7x2 =
14 u |
230 |
90% =
90100 =
910 50% =
50100 =
12 30% =
30100 =
310 The number of erasers that Owen has at first is repeated. Make the number of erasers that Owen has the same. LCM of 9 and 2 is 18 u.
The number of erasers that Tim has at first is repeated. Make the number of erasers that Tim has the same. LCM of 10 and 10 is 20 u.
Number of erasers in the end
= 9 u + 14 u
= 23 u
23 u = 230
1 u = 230 ÷ 23 = 10
Total number of erasers that the two of them have
= 18 u + 20 u
= 38 u
= 38 x 10
= 380
Answer(s): 380
