PSLE A box contained gold and orange beads. At first, the number of gold beads was
13 the number of orange beads. After
12 of the gold beads and
58 of the orange beads were used, 78 beads were left.
- What fraction of the beads were left? Leave your answer in the simplest form.
- How many beads were used?
|
Gold |
Orange |
Comparing gold beads and orange beads at first |
1x8 = 8 u |
3x8 = 24 u
|
Before
|
2x4 = 8 u |
8x3 = 24 u |
Change
|
- 1x4 = - 4 u |
- 5x3 = - 15 u |
After
|
1x4 = 4 u |
3x3 = 9 u |
(a)
The number of orange beads at first is repeated. Make the number of orange beads at first the same.
LCM of 3 and 8 is 24.
The number of gold beads at first is repeated.
Since the number of gold beads at first is 8 u, we make the total number of gold beads at first the same by multiplying 2 by 4 to become 8 u too.
Fraction of the beads left
=
4 + 98 + 24 =
1332 (b)
Number of beads left
= 4 u + 9 u
= 13 u
13 u = 78
1 u = 78 ÷ 13 = 6
Number of beads used
= 4 u + 15 u
= 19 u
= 19 x 6
= 114
Answer(s): (a)
1332; (b) 114