SOLUTION: Rachel’s piggy bank consists of P10 and P5 coins only. If there are 75 coins worth P450, how many coins of each kind does she have?

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Question 1011651: Rachel’s piggy bank consists of P10 and P5 coins only. If there are 75 coins worth P450, how many coins of each kind does she have?
Answer by Cromlix(4381) About Me  (Show Source):
You can put this solution on YOUR website!
Hi there,
Make P5 coins = x
Make P10 coins = y
x + y = 75.......(1)
5x + 10y = 450....(2)
Multiply (1) by 10
10x + 10y = 750....(1)
5x + 10y = 450.....(2)
Subtract (2) from (1)
5x .....= 300
x.......= 60
Substitute x = 60 into (1)
x + y = 75.......(1)
60 + y = 75
y = 75 - 60
y = 15
You have 60 x P5 coins
and 15 x P10 coins.
Hope this helps :-)