15 days ago, Hazel had a total of 250 blue and brown marbles. 20% of her marbles were brown marbles. Today, her older sister gave her some more marbles. As a result, her blue marbles increased by 30%. Now, 50% of her marbles are brown marbles. How many brown marbles did her older sister give her?
| |
Brown marbles |
Blue marbles |
Total
marbles |
| Before |
1 u |
4 u |
250 |
| Change |
+ 4.2 u |
+ 1.2 u |
|
| After |
5.2 u |
5.2 u |
|
Comparing the
blue marbles and
brown marbles in the end |
1 |
1 |
|
20% =
20100 =
15 Brown marbles : Blue marbles = 1 : 4
Increase in the number of blue marbles
= 30% x 4 u
=
30100 x 4 u
= 1.2 u
50% =
50100 =
12 In the end
Brown marbles : Blue marbles = 1 : 1
Number of marbles at first
= 4 u + 1 u
= 5 u
5 u = 250
1 u = 250 ÷ 5 = 50
Number of brown marbles that Hazel received from her older sister
= 5.2 u - 1 u
= 4.2 u
= 4.2 x 50
= 210
Answer(s): 210
