Ian has 10% as many pens as Dylan. If Ian gives away 20% of the pens and Dylan gives away 40% of his pens, they will have 238 pens altogether. How many pens do the two of them have?
| |
Ian |
Dylan |
Total |
Comparing Ian
and Dylan at first |
1x5 =
5 u |
10x5 =
50 u |
|
| Before |
5x1 =
5 u |
5x10 =
50 u |
|
| Change |
- 1x1 =
- 1 u |
- 2x10 =
- 20 u |
|
| After |
4x1 =
4 u |
3x10 =
30 u |
238 |
10% =
10100 =
110 20% =
20100 =
15 40% =
40100 =
25 The number of pens that Ian has at first is repeated. Make the number of pens that Ian has the same. LCM of 1 and 5 is 5 u.
The number of pens that Dylan has at first is repeated. Make the number of pens that Dylan has the same. LCM of 10 and 5 is 50 u.
Number of pens in the end
= 4 u + 30 u
= 34 u
34 u = 238
1 u = 238 ÷ 34 = 7
Total number of pens that the two of them have
= 5 u + 50 u
= 55 u
= 55 x 7
= 385
Answer(s): 385
