Last Thursday, Owen had twice as many pens as Riordan. Today, Owen gives 15 of his pens to his neighbour. Now, Riordan has thrice as many pens as Owen. How many pens does Riordan have?
| |
Owen |
Riordan |
| Before |
2x3 =
6 u |
1x3 =
3 u |
| Change |
- 15 |
|
| After |
1 u |
3 u |
The number of pens that Riordan had at first and in the end remains unchanged. Make the number of pens that Riordan has the same. LCM of 1 and 3 is 3.
Number of pens that Owen gives to his neighbour
= 6 u - 1 u
= 5 u
5 u = 15
1 u = 15 ÷ 5 = 3
Number of pens that Riordan has
= 3 u
= 3 x 3
= 9
Answer(s): 9
