10 days ago, Pamela had a total of 275 brown and yellow erasers. 20% of her erasers were yellow erasers. Today, her older sister gave her some more erasers. As a result, her brown erasers increased by 40%. Now, 50% of her erasers are yellow erasers. How many yellow erasers did her older sister give her?
| |
Yellow erasers |
Brown erasers |
Total
erasers |
| Before |
1 u |
4 u |
275 |
| Change |
+ 4.6 u |
+ 1.6 u |
|
| After |
5.6 u |
5.6 u |
|
Comparing the
brown erasers and
yellow erasers in the end |
1 |
1 |
|
20% =
20100 =
15 Yellow erasers : Brown erasers = 1 : 4
Increase in the number of brown erasers
= 40% x 4 u
=
40100 x 4 u
= 1.6 u
50% =
50100 =
12 In the end
Yellow erasers : Brown erasers = 1 : 1
Number of erasers at first
= 4 u + 1 u
= 5 u
5 u = 275
1 u = 275 ÷ 5 = 55
Number of yellow erasers that Pamela received from her older sister
= 5.6 u - 1 u
= 4.6 u
= 4.6 x 55
= 253
Answer(s): 253
