Question

At a supermarket the price of a carton of blueberries varies directly with its weight. A carton that weighs 0.5 lb cost $4.25. What is the price in dollars of a carton of blueberries that weighs 0.75 lb?

Answer 1

Given that the price of a carton of blueberries varies directly with its weight.

That is,

$p=kw,k>0$, where $p$ is the price , $w$ weight of the carton and $k$ a proportionality constant.

Consider 2 prices and weights,

$\frac{p_1}{p_2} =\frac{w_1}{w_2} \\ p_1 =\frac{w_1}{w_2} p_2\\ p_1 =\frac{0.75}{0.5} *4.25\\ p_1=6.375$

The price in dollars of a carton of blueberries that weighs 0.75 lb is $\ 6.375$.

Answer 2

It is $6.375.
0.5lb:$4.25
0.75lb:$6.375
This is because 0.75lb is 1.5 times greater than 0.5, so you do 4.25*1.5, which is $6.375