Raffles Girls Pri Sch 2007 PSLE Math Prelim Q43

There are some red and green beads in a container. If 75 more green beads are put into the container, the percentage of red beads will decrease from 30% to 20%. How many red beads are in the container?

Solution



12 units ----- 7 units + 75
5 units ----- 75
1 unit ----- 75 divided by 5 = 15

Red at first
3 units ----- 3 x 15 = 45

Answer: 45 red beads