5 days ago, Fanny had a total of 175 brown and blue erasers. 40% of her erasers were blue erasers. Today, her younger sister gave her some more erasers. As a result, her brown erasers increased by 20%. Now, 50% of her erasers are blue erasers. How many blue erasers did her younger sister give her?
| |
Blue erasers |
Brown erasers |
Total
erasers |
| Before |
2 u |
3 u |
175 |
| Change |
+ 1.6 u |
+ 0.6 u |
|
| After |
3.6 u |
3.6 u |
|
Comparing the
brown erasers and
blue erasers in the end |
1 |
1 |
|
40% =
40100 =
25 Blue erasers : Brown erasers = 2 : 3
Increase in the number of brown erasers
= 20% x 3 u
=
20100 x 3 u
= 0.6 u
50% =
50100 =
12 In the end
Blue erasers : Brown erasers = 1 : 1
Number of erasers at first
= 3 u + 2 u
= 5 u
5 u = 175
1 u = 175 ÷ 5 = 35
Number of blue erasers that Fanny received from her younger sister
= 3.6 u - 2 u
= 1.6 u
= 1.6 x 35
= 56
Answer(s): 56
