At first, Sam had 153 more gold beads than grey beads in a box. Each day, he took out 10 gold beads and 2 grey beads from the box. After some time, he only had 15 grey beads left in the box.
- How many beads did Sam take out from the box altogether?
- How many grey beads did Sam have at first?
| |
Gold beads |
Grey beads |
Comparing gold beads
and grey beads at first |
153 more |
|
| Before |
10 u |
2 u + 15 |
| Change |
- 10 u |
- 2 u |
| After |
0 |
15 |
(a)
If another 153 grey beads are added into the box at first, the number of gold and grey beads will be the same.
10 u = 2 u + 15 + 153
10 u - 2 u = 15 + 153
8 u = 168
1 u = 168 ÷ 8 = 21
Number of beads that Sam took out
= 10 u + 2 u
= 12 u
= 12 x 21
= 252
(b)
Number of beads that Sam had at first
= 252 + 15
= 267
Answer(s): (a) 252; (b) 267
