Anna and Risa had 889 erasers altogether. They decided to play a game. In the first round, Risa lost 53 erasers to Anna. In the second round, Anna lost 36 erasers to Risa. At the end of the two rounds, Risa had six times as many erasers as Anna.
- How many erasers did Anna have in the end?
- How many erasers did Risa have at the beginning of the game?
|
Anna |
Risa |
Total |
Before |
1 u + 36 - 53 |
6 u - 36 + 53 |
889 |
Round 1 |
+ 53 |
- 53 |
|
Round 2 |
- 36 |
+ 36 |
|
After |
1 u |
6 u |
889 |
(a)
Total number of erasers
= 1 u + 6 u
= 7 u
7 u = 889
1 u = 889 ÷ 7 = 127
Number of erasers that Anna had in the end
= 1 u
= 127
(b)
Working backwards.
Number of erasers that Risa had at the end of round 2
= 6 u
= 6 x 127
= 762
Number of erasers that Risa had at the end of round 1
= 762 - 36
= 726
Number of erasers that Risa had at the beginning of the game
= 726 + 53
= 779
Answer(s): (a) 127; (b) 779