Mike takes a bag containing thirty R5 and R2 coins to the bank.in exchathe bank gives him back R90 in paper money .calculate how many R5 and R2 coins he had.(let there be x R2 coins

Question

These are algebraic equations

Answer 1

x=the number of R2 coins and y=the number of R5 coins.

The number of coins is 30 so x+y=30. Therefore x=30-y.

The value of the coins is R90 so 2x+5y=90. Substitute for x:

2(30-y)+5y=90, 60-2y+5y=90, 60+3y=90, divide through by 3:

20+y=30, so y=30-20=10, and x=30-y=20.

So there were 20 R2 coins and 10 R5 coins.