In a shop, the number of cartons of mango juice sold was
12 the number of cartons left. When 21 more cartons were sold, the total number of cartons sold was 9 less than
47 the number of cartons the shop had at first. How many cartons were left?
|
Sold |
Left |
Total |
Before |
1x7 = 7 u |
2x7 = 14 u |
3x7 = 21 u
|
Change |
+ 21 |
- 21 |
|
After |
7 u + 21 |
14 u - 21 |
21 u |
Comparing the total number of cartons sold and the total number of cartons at first |
4x3 - 9 = 12 u - 9 |
|
7x3 = 21 u |
The total number of cartons is repeated. Make the total number of cartons the same. LCM of 3 and 7 is 21.
The number of cartons sold in the end is repeated.
12 u - 9 = 7 u + 21
12 u - 7 u = 21 + 9
5 u = 30
1 u = 30 ÷ 5 = 6
Number of cartons left
= 14 u - 21
= 14 x 6 - 21
= 84 - 21
= 63
Answer(s): 63