Eric had 50 more pens than Neave. Eric gave 20% of his pens to Neave. Neave in return gave 50% of his pens to Eric. In the end, Eric had 80 more pens than Neave. How many pens did Eric have at first?
| |
Eric |
Neave |
Comparing Eric
and Peter at first |
50 more |
|
| Before |
5 u + 50 |
5 u |
| Change 1 |
- 1 u - 10 |
+ 1 u + 10 |
| After 1 |
4 u + 40 |
6 u + 10 |
| Change 2 |
+ 3 u + 5 |
- 3 u - 5 |
| After 2 |
7 u + 45 |
3 u + 5 |
20% =
20100 =
1520% x 50
=
20100 x 50
= 10
50% x 10
=
50100 x 10
= 5
50% x 6 u
=
50100 x 6 u
= 3 u
Eric had 80 more pens than Neave in the end. If another 80 pens are given to Neave, both will have the same number of pens.
7 u + 45 = 3 u + 5 + 80
7 u - 3 u = 5 + 80 - 45
2 u = 40
1 u = 40 ÷ 2 = 20
Number of Eric's pens at first
= 5 u + 50
= 5 x 20 + 50
= 100 + 50
= 150
Answer: 150
