P6 / Nanyang / 2019 / SA1 / Paper 2 – Q17 [5 marks]

Question:

Jolene had some red, yellow and blue beads. The ratio of the number of red beads to the number of yellow beads was 2 : 3. The ratio of the number of yellow beads to the number of blue beads was 4 : 1. She then bought some blue beads and lost 9 red beads. In the end, the ratio of the number of red beads to the total number of yellow and blue beads became 1 : 6 and the ratio of the number of yellow beads to the number of blue beads became 2 : 3.
(a) At first, what was the ratio of the number of red beads to the number of yellow beads to the number of blue beads?
(b) How many blue beads did she buy?

Solution: