At first, Eric had 167 more red beads than grey beads in a box. Each day, he took out 8 red beads and 4 grey beads from the box. After some time, he only had 21 grey beads left in the box.
- How many beads did Eric take out from the box altogether?
- How many grey beads did Eric have at first?
| |
Red beads |
Grey beads |
Comparing red beads
and grey beads at first |
167 more |
|
| Before |
8 u |
4 u + 21 |
| Change |
- 8 u |
- 4 u |
| After |
0 |
21 |
(a)
If another 167 grey beads are added into the box at first, the number of red and grey beads will be the same.
8 u = 4 u + 21 + 167
8 u - 4 u = 21 + 167
4 u = 188
1 u = 188 ÷ 4 = 47
Number of beads that Eric took out
= 8 u + 4 u
= 12 u
= 12 x 47
= 564
(b)
Number of beads that Eric had at first
= 564 + 21
= 585
Answer(s): (a) 564; (b) 585
