Question 1 · Fractions · part-whole remainder
A bag contains ten-cent, twenty-cent and fifty-cent coins. 3/4 of the coins are ten-cent coins and 2/3 of the remaining coins are 20-cent coins. The rest of the coins are 50-cent coins. If there are 15 fifty-cent coins, how many coins are there in the bag altogether?
Step 1. Draw the whole bag as one bar. Three quarters are ten-cent coins. Cut the remaining quarter into thirds: two thirds are 20-cent, one third is 50-cent. That makes 12 equal units.
Step 2. The 50-cent coins are 1 unit out of 12, and there are 15 of them.
1 unit = 15 coins
12 units = 15 × 12
12 units = 180 coins
Ans = 180 coins


