Question

A soft drink costs $1.65, and each refill for the drink costs 0.95. If you have $4.50, how many refills can you purchase?

Answer 1

There are 3 refills

Explanation:

`color(purple)("The trick with algebra is to aske yourself: how would I do this with just numbers.")` `color(purple)("Then put in letters for the unknown values.")`

`color(green)("initial cost + total refill cost = total cost")`

`color(purple)("Let the count of refills be "r)`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

`=> color(brown)($1.65+r$0.95=$4.50)`

Dropping the dollar sign and subtracting `color(blue)(1.65)` from both sides we have:

`color(brown)(1.65color(blue)(-1.65)+r0.95=4.50color(blue)(-1.65))`

`0+r0.95= 2.85`

Divide both sides by 0.95

`rxx0.95/0.95=2.85/0.95`

But `0.95/0.95=1` giving

`r=2.85/0.95=3`

So there are 3 refills