PSLEAt first, Leah had a total of 70 black and grey balloons. 19 grey balloons burst. She then increased the number of black balloons by 75%. After that, Leah had a total of 81 balloons. How many grey balloons did she have at first?
|
Black |
Grey |
Total |
Before |
4 u |
|
70 |
Change |
+ 3 u |
- 19 |
+ 11 |
After |
7 u |
|
81 |
75100 =
34Increase in the number of balloons
= 81 - 70
= 11
3 u = 11 + 19
3 u = 30
1 u = 30 ÷ 3 = 10
Number of black balloons at first
= 4 u
= 4 x 10
= 40
Number of grey balloons at first
= 70 - 40
= 30
Answer(s): 30