10 days ago, Tiffany had a total of 120 gold and green erasers. 25% of her erasers were green erasers. Today, her father gave her some more erasers. As a result, her gold erasers increased by 40%. Now, 50% of her erasers are green erasers. How many green erasers did her father give her?
| |
Green erasers |
Gold erasers |
Total
erasers |
| Before |
1 u |
3 u |
120 |
| Change |
+ 3.2 u |
+ 1.2 u |
|
| After |
4.2 u |
4.2 u |
|
Comparing the
gold erasers and
green erasers in the end |
1 |
1 |
|
25% =
25100 =
14 Green erasers : Gold erasers = 1 : 3
Increase in the number of gold erasers
= 40% x 3 u
=
40100 x 3 u
= 1.2 u
50% =
50100 =
12 In the end
Green erasers : Gold erasers = 1 : 1
Number of erasers at first
= 3 u + 1 u
= 4 u
4 u = 120
1 u = 120 ÷ 4 = 30
Number of green erasers that Tiffany received from her father
= 4.2 u - 1 u
= 3.2 u
= 3.2 x 30
= 96
Answer(s): 96
