Anna had 54 more chocolate bars than Risa. Anna used
67 of her chocolate bars and Risa used
23 of her chocolate bars. In the end, Anna had 3 times as much as Risa. Find the number of chocolate bars that Risa had at first.
|
Anna |
Risa |
Comparing Anna and Parry at first |
54 more |
|
Before |
7x3 = 21 u |
3 u |
Change |
- 6x3 = - 18 u |
- 2 u |
After |
1x3 = 3 u |
1 u |
Comparing Anna and Parry in the end |
3 u |
1 u |
The number of chocolate bars that Anna had in the end is repeated. Make the number of chocolate bars that Anna had in the end the same. LCM of 1 and 3 is 3.
Number of chocolate bars that Anna had more than Risa
= 21 u - 3 u
= 18 u
18 u = 54
1 u = 54 ÷ 18 = 3
Number of chocolate bars that Risa had at first
= 3 u
= 3 x 3
= 9
Answer(s): 9