Inequalities word problem

Question

Norma earns $27 per hour. She donates 4% of her wages to her favorite charity. If she wants to have at least $891 left after her donation, how many hours (H) must she work? (Round the number of hours up to the next whole hour.)

Answer 1

The set up for this problem is

 

H=hours worked

 

H*27*(1-0.04)≥891

**  This represents     Hours * $27perhour * (100%-4%) is greater than or equal to $891  **

 

So H*27*(1-0.04)≥891          simplifies as follows    

 

H*27*(0.96)≥891                  Subtracted .04 from 1

 

H*25.92≥891                        Multiplied 27 by .96

 

H≥34.375                             Divided 891 by 25.92

 

 

The result is Norma has to work more than 34.375 hours.  Rounding to the nearest hour, she has to work 35 hours.