Zara had 126 less chocolate bars than Mary. Mary used
67 of her chocolate bars and Zara used
23 of her chocolate bars. In the end, Mary had 3 times as much as Zara. Find the number of chocolate bars that Mary had at first.
| |
Mary |
Zara |
Comparing Mary
and Parry at first |
|
126 less |
| Before |
7x3 =
21 u |
3 u |
| Change |
- 6x3 =
- 18 u |
- 2 u |
| After |
1x3 =
3 u |
1 u |
Comparing Mary
and Parry in the end |
3 u |
1 u |
The number of chocolate bars that Mary had in the end is repeated. Make the number of chocolate bars that Mary had in the end the same. LCM of 1 and 3 is 3.
Number of chocolate bars that Zara had less than Mary
= 21 u - 3 u
= 18 u
18 u = 126
1 u = 126 ÷ 18 = 7
Number of chocolate bars that Mary had at first
= 21 u
= 21 x 7
= 147
Answer(s): 147
