Howard has 70% as many pens as Sean. If Howard gives away 25% of the pens and Sean gives away 75% of his pens, they will have 310 pens altogether. How many pens do the two of them have?
| |
Howard |
Sean |
Total |
Comparing Howard
and Sean at first |
7x4 =
28 u |
10x4 =
40 u |
|
| Before |
4x7 =
28 u |
4x10 =
40 u |
|
| Change |
- 1x7 =
- 7 u |
- 3x10 =
- 30 u |
|
| After |
3x7 =
21 u |
1x10 =
10 u |
310 |
70% =
70100 =
710 25% =
25100 =
14 75% =
75100 =
34 The number of pens that Howard has at first is repeated. Make the number of pens that Howard has the same. LCM of 7 and 4 is 28 u.
The number of pens that Sean has at first is repeated. Make the number of pens that Sean has the same. LCM of 10 and 4 is 40 u.
Number of pens in the end
= 21 u + 10 u
= 31 u
31 u = 310
1 u = 310 ÷ 31 = 10
Total number of pens that the two of them have
= 28 u + 40 u
= 68 u
= 68 x 10
= 680
Answer(s): 680
