There are 25% more black erasers than grey erasers in a bag. After Liam removed 40% of the black erasers and increased the number of grey erasers by 35%, there are now 216 fewer black erasers than grey erasers. Find the number of grey erasers at first.
|
Black |
Grey |
Before |
5 u |
4 u |
Change |
- 2 u |
+ 1.4 u |
After |
3 u |
5.4 u |
Number of black erasers in percentage
= 100% + 25%
= 125%
125% =
125100 =
54Number of black erasers that Liam removed
= 40% x 5 u
=
40100 x 5 u
= 2 u
Number of grey erasers that Liam increased
= 35% x 4 u
=
35100 x 4 u
= 1.4 u
Number of black erasers in the end
= 5 u - 2 u
= 3 u
Number of grey erasers in the end
= 4 u + 1.4 u
= 5.4 u
Number of fewer black erasers than grey erasers in the end
= 5.4 u - 3 u
= 2.4 u
2.4 u = 216
1 u = 216 ÷ 2.4 = 90
Number of grey erasers at first
= 4 u
= 4 x 90
= 360
Answer(s): 360