Let #x# represent the original price of the laptop.
Price . . . . . . #x# #larr# original cost
Then #16%# of that cost is added
#16%# of #x = 0.16x#
Adding #(0.16 x)# to #x# . . . . #x + 0.16x# #larr# cost plus #16%#
Together, they add up to #$960#
[cost] plus [16% of cost] = [total price]
[ . #x# .] . . + . [. . . #0.16x# . . ] = [ . . #960# . . .]
#1x + 0.16x = 960#
Solve for #x#, already defined as the pre-tax cost
1) Combine like terms
#1.16x = 960#
2) Divide both sides by #1.16# to isolate #x#, previously defined as the pre-tax cost
#x = 827.59# #larr# answer
............................
Check
#$827.59 + 16%# of #$827.59# should add up to #$960#
Pre-tax cost . . . . . . . . . . . #$827.59#
#16%# of #$827.59# . . . . . . . #$132.51# #larr# Amount of tax
...................................................................
Price including tax . . . . . .#$960.10# #larr# 10ȼ rounding error
#Check!#
