There are some gold and blue beads in a box. If 2 gold beads are removed from the box, the total number of beads left will be 4 times the number of gold beads left. If 3 blue beads are removed from the box, the total number of beads left will be 3 times the number of gold beads. How many beads are there in the box?
|
Case 1 |
Case 2 |
|
Gold beads |
Blue beads |
Gold beads |
Blue beads |
Before |
1 u + 2 |
3 u |
1 p |
2 p + 3 |
Change |
- 2 |
|
|
- 3 |
After |
1 u |
3 u |
1 p |
2 p |
Number of blue beads in the end for Case 1
= 4 u - 1 u
= 3 u
Number of gold beads in the end for Case 2
= 3 p - 1 p
= 2 p
The number of gold beads at first is the same for Case 1 and Case 2.
The number of blue beads at first is also the same for Case 1 and Case 2.
1 u + 2 = 1 p --- (1)
3 u = 2 p + 3
3 u - 3 =
2 p --- (2)
Make p the same.
(1)
x2 2 u + 4 =
2 p --- (3)
(2) = (3)
3 u - 3 = 2 u + 4
3 u - 2 u = 4 + 3
1 u = 7
1 u = 7 ÷ 1 = 7
Number of beads in the box
= (1 u + 2) + 3 u
= 4 u + 2
= (4 x 7) + 2
= 28 + 2
= 30
Answer(s): 30