There are some gold and yellow beads in a box. If 7 gold beads are removed from the box, the total number of beads left will be 9 times the number of gold beads left. If 58 yellow 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 |
Yellow beads |
Gold beads |
Yellow beads |
Before |
1 u + 7 |
8 u |
1 p |
2 p + 58 |
Change |
- 7 |
|
|
- 58 |
After |
1 u |
8 u |
1 p |
2 p |
Number of yellow beads in the end for Case 1
= 9 u - 1 u
= 8 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 yellow beads at first is also the same for Case 1 and Case 2.
1 u + 7 = 1 p --- (1)
8 u = 2 p + 58
8 u - 58 =
2 p --- (2)
Make p the same.
(1)
x2 2 u + 14 =
2 p --- (3)
(2) = (3)
8 u - 58 = 2 u + 14
8 u - 2 u = 14 + 58
6 u = 72
1 u = 72 ÷ 6 = 12
Number of beads in the box
= (1 u + 7) + 8 u
= 9 u + 7
= (9 x 12) + 7
= 108 + 7
= 115
Answer(s): 115