Andy and George had some pens in the ratio of 11 : 6. George and Pierre had some pens in the ratio of 10 : 9. Andy sold 280 pens to Pierre and ended up with half the number of pens George had. How many pens did Pierre have in the end?
| Andy |
George |
Pierre |
| 11x5 |
6x5 |
|
| |
10x3 |
9x3 |
| 55 u |
30 u |
27 u |
The number of pens that George had at first is repeated. Make the number of pens that George had at first the same. LCM of 6 and 10 is 30.
| |
Andy |
George |
Pierre |
| Before |
55 u |
30 u |
27 u |
| Change |
- 280 |
|
+ 280 |
| After |
15 u |
30 u |
27 u + 280 |
Number of pens that Andy had in the end
= 30 u ÷ 2
= 15 u
Number of pens that Andy sold to Pierre
= 55 u - 15 u
= 40 u
40 u = 280
1 u = 280 ÷ 40 = 7
Number of pens that Pierre had in the end
= 27 u + 280
= 27 x 7 + 280
= 189 + 280
= 469
Answer(s): 469
