Justin has 30% as many pens as Henry. If Justin gives away 25% of the pens and Henry gives away 10% of his pens, they will have 360 pens altogether. How many pens do the two of them have?
| |
Justin |
Henry |
Total |
Comparing Justin
and Henry at first |
3x4 =
12 u |
10x4 =
40 u |
|
| Before |
4x3 =
12 u |
10x4 =
40 u |
|
| Change |
- 1x3 =
- 3 u |
- 1x4 =
- 4 u |
|
| After |
3x3 =
9 u |
9x4 =
36 u |
360 |
30% =
30100 =
310 25% =
25100 =
14 10% =
10100 =
110 The number of pens that Justin has at first is repeated. Make the number of pens that Justin has the same. LCM of 3 and 4 is 12 u.
The number of pens that Henry has at first is repeated. Make the number of pens that Henry has the same. LCM of 10 and 10 is 40 u.
Number of pens in the end
= 9 u + 36 u
= 45 u
45 u = 360
1 u = 360 ÷ 45 = 8
Total number of pens that the two of them have
= 12 u + 40 u
= 52 u
= 52 x 8
= 416
Answer(s): 416
