You have twice as many 20 cent coins as 10 cents coins and half the number of 5 cent coins as 10 cent coins. If you have R4,20 altogether, find out how many of each coin denomination do you have?

1 answer

suppose you have x,y,z of 5¢, 10¢, 20¢ coins, respectively. Then you know that
z = 2y
y = 2x
5x+10y+20z = 420
Now just solve as usual