At first, Sam had 118 more silver beads than black beads in a box. Each day, he took out 8 silver beads and 4 black beads from the box. After some time, he only had 42 black beads left in the box.
- How many beads did Sam take out from the box altogether?
- How many black beads did Sam have at first?
| |
Silver beads |
Black beads |
Comparing silver beads
and black beads at first |
118 more |
|
| Before |
8 u |
4 u + 42 |
| Change |
- 8 u |
- 4 u |
| After |
0 |
42 |
(a)
If another 118 black beads are added into the box at first, the number of silver and black beads will be the same.
8 u = 4 u + 42 + 118
8 u - 4 u = 42 + 118
4 u = 160
1 u = 160 ÷ 4 = 40
Number of beads that Sam took out
= 8 u + 4 u
= 12 u
= 12 x 40
= 480
(b)
Number of beads that Sam had at first
= 480 + 42
= 522
Answer(s): (a) 480; (b) 522
