jordanJordan has a jar of quarters. When he has 60 quarters in the jar, the jar weighs 52 ounces. When there are 125 quarters in the jar, the jar weighs 65 ounces. What is the weight of the empty jar?

Question

AZ · Answer

60 quarters - the jar weights 52 ounces

125 quarters - the jar weights 65 ounces

Obviously the weight is weight of the jar + weight of the quarters

We first have to find the weight of the quarters and then we can find the weight of the jar

AZ · Answer

60 quarters = 52 ounces
125 quarters = 65 ounces

So do a simple subtraction

125 quarters - 60 quarters = ??

and what would the weight of that many quarters be?

65 ounces - 52 ounces = ??

What do you get?

AZ · Answer

Then we can try to find the weight of 1 quarter

and then multiply by 60 to get the weight of 60 quarters

and then we subtract that from 52 ounces to find out the weight of an empty jar
(since the weight of a jar with 60 quarters is 52 ounces, so if we subtract the weight of 60 quarters then we would get the weight of the empty jar)

crispyrat · Answer

let j be the weight of the jar and q the weight of a quarter
60q+j=52
and
125q+j=65
So using the first equation
j=52-60q
then just plug it in and then you solve for j