Question 1177307
Hannah and James are married. Every Saturday they take turns to clean their apartment.
 Hannah cleans it fast in 3 hours because she does not like to clean.
 James listens to music, texts, and takes his time while cleaning.
 He takes 5 hours. They finally decided to do it together.
 How long will it take?
;
Let t = time required when working together
let the completed job = 1 (A clean apt)
:
Each will do a fraction of the job, the two fractions add up to 1
{{{t/3}}} + {{{t/5}}} = 1
multiply eq by 15, cancel the denominators
8t = 15
t = 15/8
t = 1.875 hrs which is 1 + .875(60) = l hr and 52.5 min
5t + 3t = 15