There are some brown and green marbles in a container. If 10 brown marbles are removed from the container, the total number of marbles left will be 9 times the number of brown marbles left. If 40 green marbles are removed from the container, the total number of marbles left will be 3 times the number of brown marbles. How many marbles are there in the container?
|
Case 1 |
Case 2 |
|
Brown marbles |
Green marbles |
Brown marbles |
Green marbles |
Before |
1 u + 10 |
8 u |
1 p |
2 p + 40 |
Change |
- 10 |
|
|
- 40 |
After |
1 u |
8 u |
1 p |
2 p |
Number of green marbles in the end for Case 1
= 9 u - 1 u
= 8 u
Number of brown marbles in the end for Case 2
= 3 p - 1 p
= 2 p
The number of brown marbles at first is the same for Case 1 and Case 2.
The number of green marbles at first is also the same for Case 1 and Case 2.
1 u + 10 = 1 p --- (1)
8 u = 2 p + 40
8 u - 40 =
2 p --- (2)
Make p the same.
(1)
x2 2 u + 20 =
2 p --- (3)
(2) = (3)
8 u - 40 = 2 u + 20
8 u - 2 u = 20 + 40
6 u = 60
1 u = 60 ÷ 6 = 10
Number of marbles in the container
= (1 u + 10) + 8 u
= 9 u + 10
= (9 x 10) + 10
= 90 + 10
= 100
Answer(s): 100