At first, Peter had 122 more white beads than blue beads in a box. Each day, he took out 7 white beads and 3 blue beads from the box. After some time, he only had 42 blue beads left in the box.
- How many beads did Peter take out from the box altogether?
- How many blue beads did Peter have at first?
| |
White beads |
Blue beads |
Comparing white beads
and blue beads at first |
122 more |
|
| Before |
7 u |
3 u + 42 |
| Change |
- 7 u |
- 3 u |
| After |
0 |
42 |
(a)
If another 122 blue beads are added into the box at first, the number of white and blue beads will be the same.
7 u = 3 u + 42 + 122
7 u - 3 u = 42 + 122
4 u = 164
1 u = 164 ÷ 4 = 41
Number of beads that Peter took out
= 7 u + 3 u
= 10 u
= 10 x 41
= 410
(b)
Number of beads that Peter had at first
= 410 + 42
= 452
Answer(s): (a) 410; (b) 452
