Ivan has 10% as many erasers as Daniel. If Ivan gives away 50% of the erasers and Daniel gives away 90% of his erasers, they will have 33 erasers altogether. How many erasers do the two of them have?
| |
Ivan |
Daniel |
Total |
Comparing Ivan
and Daniel at first |
1x2 =
2 u |
10x2 =
20 u |
|
| Before |
2x1 =
2 u |
10x2 =
20 u |
|
| Change |
- 1x1 =
- 1 u |
- 9x2 =
- 18 u |
|
| After |
1x1 =
1 u |
1x2 =
2 u |
33 |
10% =
10100 =
110 50% =
50100 =
12 90% =
90100 =
910 The number of erasers that Ivan has at first is repeated. Make the number of erasers that Ivan has the same. LCM of 1 and 2 is 2 u.
The number of erasers that Daniel has at first is repeated. Make the number of erasers that Daniel has the same. LCM of 10 and 10 is 20 u.
Number of erasers in the end
= 1 u + 2 u
= 3 u
3 u = 33
1 u = 33 ÷ 3 = 11
Total number of erasers that the two of them have
= 2 u + 20 u
= 22 u
= 22 x 11
= 242
Answer(s): 242
