<PRE><B>Question 302313</B>
let x = no. of $5 bills
Let y = no. of $1 bills
:
A cash register has 43 bills, all of them 5 dollar and 1 dollar bills.
x + y = 43
:
The combined monetary value of the bills is $167.
5x + 1y = 167
:
Find the number of each denomination.
Subtract the 1st equation from the 2nd equation
5x + y = 167
 x + y =  43
-----------------Subtraction eliminates y find x
4x = 124
x = {{{124/4}}}
x = 31 ea $5 bills
Find y
31 + y = 43
y = 43 - 31
y = 12 ea $1 bills
:
Check in the total$ equation
5(31) + 12 = 167
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