Question

The price of 600 grams of candy and 1.5 kg of cookies was 4 dollars and 62 cents. What is the price of one kg of cookies if it is 1 dollar and 40 cents cheaper than 1 kg of candy? (1 kg = 1,000g)

Answer 1

The price of the kilogram of cookies is $ 1.8

Explanation:

Call x the price of the kilogram of candy and call y the price of kilogram of cookies

Then we know that

`0.600x + 1.5y = 4.62`

We also know that the price of kilogram of cookies is 1.40 dollars cheaper than the kilogram of candy

So

`y = x-1.40`

We solve this equation for x and then we substitute it in the first equation.

`x = y + 1.40`

`0.60 (y +1.40) + 1.5y = 4.62\\\\0.60y + 1.5y = 4.62 - 0.84\\\\2.1y = 3.78`

`y = \$1.8`