Jeremy has a carton containing some bunches of purple grapes and bunches of green grapes. If he adds in 27 bunches of purple grapes, 0.7 of the bunches of grapes in the carton will be bunches of green grapes. If he adds in 51 bunches of green grapes,
34 of the bunches of grapes in the carton will be green bunches of grapes. How many bunches of grapes are there in the carton?
|
Bunches of green grapes |
Bunches of purple grapes |
Bunches of green grapes |
Bunches of purple grapes |
Before |
7 u |
3 u - 27 |
3 p - 51 |
1 p |
Change |
|
+ 27 |
+ 51 |
|
After |
7 u |
3 u |
3 p |
1 p |
0.7 =
710 =
710If he adds 27 bunches of purple grapes,
Number of bunches of purple grapes in the end
= 10 u - 7 u
= 3 u
If he adds 51 bunches of green grapes,
Number of bunches of purple grapes in the end
= 4 p - 3 p
= 1 p
The number of each type in both scenarios remain unchanged at first.
7 u = 3 p - 51 --- (1)
3 u - 27 = 1 p
3 u = 1 p + 27 --- (2)
Make u the same.
(1)
x3 21 u = 9 p - 153 --- (3)
(2)
x7 21 u = 7 p + 189 --- (4)
(3) = (4)
9 p - 153 = 7 p + 189
9 p - 7 p = 153 + 189
2 p = 342
1 p = 342 ÷ 2 = 171
Number of bunches of grapes at first
= 1 p + 3 p - 51
= 4 p - 51
= 4 x 171 - 51
= 684 - 51
= 633
Answer(s): 633