At first, Charlie had 117 more black beads than red beads in a box. Each day, he took out 10 black beads and 5 red beads from the box. After some time, he only had 58 red beads left in the box.
- How many beads did Charlie take out from the box altogether?
- How many red beads did Charlie have at first?
| |
Black beads |
Red beads |
Comparing black beads
and red beads at first |
117 more |
|
| Before |
10 u |
5 u + 58 |
| Change |
- 10 u |
- 5 u |
| After |
0 |
58 |
(a)
If another 117 red beads are added into the box at first, the number of black and red beads will be the same.
10 u = 5 u + 58 + 117
10 u - 5 u = 58 + 117
5 u = 175
1 u = 175 ÷ 5 = 35
Number of beads that Charlie took out
= 10 u + 5 u
= 15 u
= 15 x 35
= 525
(b)
Number of beads that Charlie had at first
= 525 + 58
= 583
Answer(s): (a) 525; (b) 583
