There are some silver and blue balls in a box. If 2 silver balls are removed from the box, the total number of balls left will be 6 times the number of silver balls left. If 32 blue balls are removed from the box, the total number of balls left will be 3 times the number of silver balls. How many balls are there in the box?
|
Case 1 |
Case 2 |
|
Silver balls |
Blue balls |
Silver balls |
Blue balls |
Before |
1 u + 2 |
5 u |
1 p |
2 p + 32 |
Change |
- 2 |
|
|
- 32 |
After |
1 u |
5 u |
1 p |
2 p |
Number of blue balls in the end for Case 1
= 6 u - 1 u
= 5 u
Number of silver balls in the end for Case 2
= 3 p - 1 p
= 2 p
The number of silver balls at first is the same for Case 1 and Case 2.
The number of blue balls at first is also the same for Case 1 and Case 2.
1 u + 2 = 1 p --- (1)
5 u = 2 p + 32
5 u - 32 =
2 p --- (2)
Make p the same.
(1)
x2 2 u + 4 =
2 p --- (3)
(2) = (3)
5 u - 32 = 2 u + 4
5 u - 2 u = 4 + 32
3 u = 36
1 u = 36 ÷ 3 = 12
Number of balls in the box
= (1 u + 2) + 5 u
= 6 u + 2
= (6 x 12) + 2
= 72 + 2
= 74
Answer(s): 74