At first, Cole had 109 more purple beads than grey beads in a box. Each day, he took out 10 purple beads and 7 grey beads from the box. After some time, he only had 29 grey beads left in the box.
- How many beads did Cole take out from the box altogether?
- How many grey beads did Cole have at first?
| |
Purple beads |
Grey beads |
Comparing purple beads
and grey beads at first |
109 more |
|
| Before |
10 u |
7 u + 29 |
| Change |
- 10 u |
- 7 u |
| After |
0 |
29 |
(a)
If another 109 grey beads are added into the box at first, the number of purple and grey beads will be the same.
10 u = 7 u + 29 + 109
10 u - 7 u = 29 + 109
3 u = 138
1 u = 138 ÷ 3 = 46
Number of beads that Cole took out
= 10 u + 7 u
= 17 u
= 17 x 46
= 782
(b)
Number of beads that Cole had at first
= 782 + 29
= 811
Answer(s): (a) 782; (b) 811
