Lynn and Nicole have some pens. If Lynn gives 21 pens to Nicole, Nicole will have 5 times the number of pens as Lynn. If Nicole gives 39 pens to Lynn, Lynn will have
35 as many pens as Nicole. How many pens does Lynn have at first?
| |
Case 1 |
Case 2 |
| |
Lynn |
Nicole |
Lynn |
Nicole |
| Before |
4 u + 21 |
20 u - 21 |
9 u - 39 |
15 u + 39 |
| Change |
- 21 |
+ 21 |
+ 39 |
- 39 |
| After |
1x4 =
4 u |
5x4 =
20 u |
3x3 =
9 u |
5x3 =
15 u |
The total number of pens in both cases remains unchanged. Make the total number of pens in both cases the same. LCM of 6 and 8 is 24.
Number of pens that Lynn had at first is the same in both cases.
9 u - 39 = 4 u + 21
9 u - 4 u = 21 + 39
5 u = 60
1 u = 12
Number of pens that Lynn had at first
= 4 u + 21
= 4 x 12 + 21
= 48 + 21
= 69
Answer(s): 69
