Lynn and Peter collect coins and pens. Peter has 40 less coins than pens. Peter has 2 times the number of coins Lynn has, and Lynn has 20% more pens than Peter. After Lynn gives Peter all of her coins and Peter gives Lynn 70% of his pens, Peter has 36 more coins than pens. Find the number of pens Lynn has at first.
| Lynn |
Peter |
| Pens |
Coins |
Pens |
Coins |
| 2.4 u + 48 |
1 u |
2 u + 40 |
2 u |
| + 1.4 u + 28 |
- 1 u |
- 1.4 u - 28 |
+ 1 u |
| 3.8 u + 76 |
0 |
0.6 u + 12 |
3 u |
100%+ 20% = 120%
120% x 2 u
=
120100 x 2 u
= 2.4 u
120% x 40
=
120100 x 40
= 48
70% x 2 u
=
70100 x 2 u
= 1.4 u
70% x 40
=
70100 x 40
= 28
If another 36 pens are given to Peter, he will have equal number of pens and coins in the end.
3 u = 0.6 u + 12 + 36
3 u - 0.6 u = 48
2.4 u = 48
1 u = 48 ÷ 2.4 = 20
Number of pens that Lynn has at first
= 2.4 u + 48
= 2.4 x 20 + 48
= 48 + 48
= 96
Answer(s): 96 
