PSLE A box contained purple and green beads. At first, the number of purple beads was
13 the number of green beads. After
12 of the purple beads and
14 of the green beads were used, 88 beads were left.
- What fraction of the beads were used? Leave your answer in the simplest form.
- How many beads were there in the box at first?
|
Purple |
Green |
Comparing purple beads and green beads at first |
1x4 = 4 u |
3x4 = 12 u
|
Before
|
2x2 = 4 u |
4x3 = 12 u |
Change
|
- 1x2 = - 2 u |
- 1x3 = - 3 u |
After
|
1x2 = 2 u |
3x3 = 9 u |
(a)
The number of green beads at first is repeated. Make the number of green beads at first the same. LCM of 3 and 4 is 12.
The number of purple beads at first is repeated.
Since the number of purple beads at first is 4 u, we make the total number of purple beads at first the same by multiplying 2 by 2 to become 4 u too.
Fraction of the beads used
=
2 + 34 + 12 =
516 (b)
Number of beads left
= 2 u + 9 u
= 11 u
11 u = 88
1 u = 88 ÷ 11 = 8
Number of beads at first
= 16 u
= 16 x 8
= 128
Answer(s): (a)
516; (b) 128