Dana and Shiyun have some pens in the ratio 3 : 11. Dana has 40 less pens than Shiyun. How many pens must Shiyun give to Dana so that they will have the same number of pens?
| |
Dana |
Shiyun |
Total |
| Before |
3 u |
11 u |
14 u |
| Change |
+ 4 u |
- 4 u |
|
After |
1x7 =
7 u |
1x7 =
7 u |
2x7 =
14 u |
The total number of pens remains unchanged. Make the total number of pens at first and in the end the same. LCM of 2 and 14 is 14.
Difference in the number of pens at first
= 11 u - 3 u
= 8 u
8 u = 40
1 u = 40 ÷ 8 = 5
Number of pens that each of them had in the end
= 14 u ÷ 2
= 7 u
Number of pens that Shiyun must give to Dana
= 7 u - 3 u
= 4 u
= 4 x 5
= 20
Answer(s): 20
