Question

If peter pays $84 to buy a watch after a discount of 20% find the original price of the watch

Answer 1

Let $x be the original price of the watch. Then $(x-84) is the sum of a discount.

So we obtain the equation:

$x - 84 = 0.2 x; \newline x - 0.2x = 84; \newline 0.8x = 84; \newline x =\frac{84}{0.8}; \newline x = 105$

Thus, the original price of the watch is $105.