Question
PSLE
At first, a box contained 12 brown marbles and some red beads. After some brown marbles were added, 25 of the marbles were red. After 20 black marbles were added to the box and now, 27 of the beads were red. What was the number of brown marbles added?
2 m

Click button first when a symbol is required. X

PSLE
At first, a box contained 12 brown marbles and some red beads. After some brown marbles were added, 25 of the marbles were red. After 20 black marbles were added to the box and now, 27 of the beads were red. What was the number of brown marbles added?