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?

1 Answer
Nov 11, 2016

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