PSLE
A box contained red and green beads. At first, the number of red beads was ¹₄ the number of green beads. After ¹₃ of the red beads and ⁷₉ of the green beads were used, 140 beads were left.

1. What fraction of the beads were left? Leave your answer in the simplest form.
2. How many beads were used?

	Red	Green
Comparing red beads and green beads at first	1x9 = 9 u	4x9 = 36 u
Before	3x3 = 9 u	9x4 = 36 u
Change	- 1x3 =  - 3 u	- 7x4 = - 28 u
After	2x3 =  6 u	2x4 = 8 u

(a)
The number of green beads at first is repeated. Make the number of green beads at first the same. 
LCM of 4 and 9 is 36.

The number of red beads at first is repeated.

Since the number of red beads at first is 9 u, we make the total number of red beads at first the same by multiplying 3 by 3 to become 9 u too.

Fraction of the beads left
= ^{6 + 8}_{9 + 36} 
= ¹⁴₄₅

(b)
Number of beads left
= 6 u + 8 u
= 14 u

14 u = 140

1 u = 140 ÷ 14 = 10

Number of beads used
= 3 u + 28 u
= 31 u
= 31 x 10
= 310

Answer(s): (a) ¹⁴₄₅; (b) 310