PSLEAt first, Leah had a total of 79 grey and red balloons. 20 red balloons burst. She then increased the number of grey balloons by 70%. After that, Leah had a total of 87 balloons. How many red balloons did she have at first?
|
Grey |
Red |
Total |
Before |
10 u |
|
79 |
Change |
+ 7 u |
- 20 |
+ 8 |
After |
17 u |
|
87 |
70100 =
710Increase in the number of balloons
= 87 - 79
= 8
7 u = 8 + 20
7 u = 28
1 u = 28 ÷ 7 = 4
Number of grey balloons at first
= 10 u
= 10 x 4
= 40
Number of red balloons at first
= 79 - 40
= 39
Answer(s): 39