At first, David had 143 more pink beads than blue beads in a box. Each day, he took out 9 pink beads and 2 blue beads from the box. After some time, he only had 18 blue beads left in the box.
- How many beads did David take out from the box altogether?
- How many blue beads did David have at first?
| |
Pink beads |
Blue beads |
Comparing pink beads
and blue beads at first |
143 more |
|
| Before |
9 u |
2 u + 18 |
| Change |
- 9 u |
- 2 u |
| After |
0 |
18 |
(a)
If another 143 blue beads are added into the box at first, the number of pink and blue beads will be the same.
9 u = 2 u + 18 + 143
9 u - 2 u = 18 + 143
7 u = 161
1 u = 161 ÷ 7 = 23
Number of beads that David took out
= 9 u + 2 u
= 11 u
= 11 x 23
= 253
(b)
Number of beads that David had at first
= 253 + 18
= 271
Answer(s): (a) 253; (b) 271
