Victoria had four boxes, U, V, W and X which contained a total of 207 pears. She transferred 10 pears from Box U to Box V, 36 pears from Box V to Box W and 77 pears from Box W to Box X. The ratio of the number of pears in Box U to Box V to Box W changed from 2 : 6 : 11 to 1 : 4 : 9. How many pears were in Box X at first?
|
Make p the same (1)x4 = (3) |
U (1) |
V (2) |
W
|
X
|
Before |
8 u |
2 u |
6 u |
11 u |
? |
Change 1 |
- 40 |
- 10 |
+ 10 |
|
|
Change 2 |
|
|
- 36 |
+ 36 |
|
Change 3 |
|
|
|
- 77 |
+ 77 |
After |
4 p |
1 p |
4 p |
9 p |
? |
2 u - 10 = 1 p --- (1)
6 u + 10 - 36 = 4 p
6 u - 26 =
4 p --- (2)
(1)
x 4 8 u - 40 =
4 p --- (3)
Make p the same.
(3) = (2)
8 u - 40 = 6 u - 26
8 u - 6 u = 40 - 26
2 u = 14
1 u = 14 ÷ 2 = 7
Total number of pears in Box U, Box V and Box W
= 2 u + 6 u + 11 u
= 19 u
Total number of pears in Box X at first
= 207 - 19 u
= 207 - 19 x 7
= 207 - 133
= 74
Answer(s): 74