Question

Bank teller has 500 bills totalling $8100.00. How many tens and twentys does she have

Answer 1

Let x = no. of 10's and number of 20's
:
10x + 20x + 147 = 1167
:

Answer 2

$20 bills = 310, $10 bills = 190

Explanation:

To solve this problem, we must make a system of equations

Let x = the number of $20 dollar bills and let y = the number of $10 dollar bills

A $20 bill is 20 dollars and a $10 dollar bill is 10 dollars. The money added together will equal $8100, so an equation for this would be:

20x + 10y = 8100

The number of 20 dollar bills and 10 dollar bills added together will be 500 bills, so that equation would be:

x + y = 500

Now we have our system of equation! To solve this, we will use substitution.

If x + y = 500, then x = 500 - y.

We can substitute this into x in the first equation.

20x + 10y = 8100 will become:

20(500 - y) + 10y = 8100

10000 - 20y + 10y = 8100

10000 - 10y = 8100

We can add 10y to both sides and subtract 8100 from both sides

1900 = 10y

Now divide both sides by 10.

190 = y

There are 190 10 dollar bills.

Plugging this value into the equation, we have:

x + y = 500

x + 190 = 500

Subtract 190 from both sides

x = 310

There are 310 20 dollar bills