Question

In a sale, Jen buys a laptop for 351.55. this price is 21% less than the price before the sale.

calculate the price before the sale.

Answer 1

Let $x be the price before sale. This price is 100%. If in a sale, Jen buys a laptop for $351.55 that is 21% less than the price before the sale, then this price is 100%-21%=79%.

Consider proportion

$x - 100%,

$351.55 - 79%,

that is mathematically

`(x)/(351.55)=(100)/(79).`

Find x:

`x=(351.55\cdot 100)/(79)=445.`

Answer: the price before the sale was $445.