There are some blue and gold beads in a box. If 10 blue beads are removed from the box, the total number of beads left will be 9 times the number of blue beads left. If 25 gold beads are removed from the box, the total number of beads left will be 4 times the number of blue beads. How many beads are there in the box?
|
Case 1 |
Case 2 |
|
Blue beads |
Gold beads |
Blue beads |
Gold beads |
Before |
1 u + 10 |
8 u |
1 p |
3 p + 25 |
Change |
- 10 |
|
|
- 25 |
After |
1 u |
8 u |
1 p |
3 p |
Number of gold beads in the end for Case 1
= 9 u - 1 u
= 8 u
Number of blue beads in the end for Case 2
= 4 p - 1 p
= 3 p
The number of blue beads at first is the same for Case 1 and Case 2.
The number of gold beads at first is also the same for Case 1 and Case 2.
1 u + 10 = 1 p --- (1)
8 u = 3 p + 25
8 u - 25 =
3 p --- (2)
Make p the same.
(1)
x3 3 u + 30 =
3 p --- (3)
(2) = (3)
8 u - 25 = 3 u + 30
8 u - 3 u = 30 + 25
5 u = 55
1 u = 55 ÷ 5 = 11
Number of beads in the box
= (1 u + 10) + 8 u
= 9 u + 10
= (9 x 11) + 10
= 99 + 10
= 109
Answer(s): 109