Question

Write an expression for the amount of change you will get when you pay for a purchase p with a 20 dollar bill. Make a table to find the amounts of change you will get for purchases of 11.59 17.50 19.00 20.00

Answer 1

Answer:

Let p be the purchase price, and c be the change.

The amounts of change means 20 dollars minus purchase amount.

The expression becomes:

$20- p =c$

When p = $11.59

$c = 20-11.59$

c = $8.41

When p = $17.50

$c = 20-17.50$

c = $2.50

When p = $19

$c = 20-19$

c = $1.00

When p = $20

$c = 20-20$

c = $0.00

Answer 2

change,c = 20 - p

so in Excel for example

put 20 in column a

put 11.59, 17.50 etc in column b

in column c put the equation '=20 - b1'