14 days ago, Dana had a total of 150 silver and green erasers. 40% of her erasers were green erasers. Today, her mother gave her some more erasers. As a result, her silver erasers increased by 20%. Now, 50% of her erasers are green erasers. How many green erasers did her mother give her?
| |
Green erasers |
Silver erasers |
Total
erasers |
| Before |
2 u |
3 u |
150 |
| Change |
+ 1.6 u |
+ 0.6 u |
|
| After |
3.6 u |
3.6 u |
|
Comparing the
silver erasers and
green erasers in the end |
1 |
1 |
|
40% =
40100 =
25 Green erasers : Silver erasers = 2 : 3
Increase in the number of silver erasers
= 20% x 3 u
=
20100 x 3 u
= 0.6 u
50% =
50100 =
12 In the end
Green erasers : Silver erasers = 1 : 1
Number of erasers at first
= 3 u + 2 u
= 5 u
5 u = 150
1 u = 150 ÷ 5 = 30
Number of green erasers that Dana received from her mother
= 3.6 u - 2 u
= 1.6 u
= 1.6 x 30
= 48
Answer(s): 48
