How to find a total given fractions

Question

One fourth of a college students weekly earnings is spent on new headphones. One third of the remaining earnings is spent on food. If the cost of food was $125, how much was the students weekly earnings?

Answer 1

So if 1/3 of the remaining money is equal to $125, then 3*1/3= 1(remaining earnings)

 

Using the value given 3*$125= $375

 

The (remaining earnings) is equal to (weekly earnings) minus (money spent on headphones)

 

(money spent on headphones) = weekly earnings multiplied by one fourth

 

(weekly earnings)= your unknown variable (x)

 

When plugged in,

$375 = x - x*(1/4) ⇒ $375 = x(1-(1/4)) ⇒ $375 = x(0.75) ⇒ $375/.75 = x ⇒ x = $500

 

Weekly earnings = $500 

 

Hope that helps.