Barbara had 135 pencils.
23 of them were brown pencils and the rest were black pencils. After she had given away some brown pencils, the ratio of the number of brown pencils to the number of black pencils became 3 : 5. How many pencils did she have in the end?
| |
Brown |
Black |
Total |
| Before |
2x5 =
10 u |
1x5 =
5 u |
3x5 =
15 u |
| Change |
- 7 u |
|
|
| After |
3 u |
5 u |
8 u |
The number of black pencils remained unchanged.
LCM of 1 and 5 = 5
Total number of pencils at first = 15 u
15 u = 135
1 u = 135 ÷ 15 = 9
Number of pencils that Barbara had in the end
= 3 u + 5 u
= 8 u
= 8 x 9
= 72
Answer(s):72
