A collection of 27 coins consists of $0.20 and $2.00 coins, and has a value of $23.40. Find the number of coins of each denomination.

Question

A collection of 27 coins consists of $0.20 and $2.00 coins, and has a value of $23.40. Find the number of coins of each denomination.

Answer 1

x= # $.20 coins

y = # $2.00 coins

 

x + y =27

.2x + 2y = 23.4

 

multiply equation 1 by -2 and add

the equations

 

-2x -2y = -54

.2x + 2y = 23.4

----------------------

-1.8x = -30.6

 

Now just solve for x to find the number

of $.20 coins.  Then 27-x will be the

number of $2.00 coins