Nahana takes 2 hours to deliver newspapers to her 125 customers. Angela delivers the same number of newspapers in 3 hours. How long will it take them to deliver the 125 newspapers if they work together? I'm so confused.

Answer 1

N delivers 125/2 papers per hour
A delivers 125/3 papers per hour
together they deliver (125/2 +125/3) papers/hr
that is really 125(1/2+1/3) = 125 (3/6+2/6) = 125 (5/6) papers/hr
so
125 (5/6) papers/hr * x hours = 125 newspapers
x = 6/5 hours = 1 1/5
1/5 hour = 60/5 = 12 minutes
so
an hour and 12 minutes