Luis has 30% as many pens as Paul. If Luis gives away 50% of the pens and Paul gives away 80% of his pens, they will have 70 pens altogether. How many pens do the two of them have?
| |
Luis |
Paul |
Total |
Comparing Luis
and Paul at first |
3x2 =
6 u |
10x2 =
20 u |
|
| Before |
2x3 =
6 u |
5x4 =
20 u |
|
| Change |
- 1x3 =
- 3 u |
- 4x4 =
- 16 u |
|
| After |
1x3 =
3 u |
1x4 =
4 u |
70 |
30% =
30100 =
310 50% =
50100 =
12 80% =
80100 =
45 The number of pens that Luis has at first is repeated. Make the number of pens that Luis has the same. LCM of 3 and 2 is 6 u.
The number of pens that Paul has at first is repeated. Make the number of pens that Paul has the same. LCM of 10 and 5 is 20 u.
Number of pens in the end
= 3 u + 4 u
= 7 u
7 u = 70
1 u = 70 ÷ 7 = 10
Total number of pens that the two of them have
= 6 u + 20 u
= 26 u
= 26 x 10
= 260
Answer(s): 260
