Question

If Rhonda can type a 1000 word report in 4 hours, and while her friend Betty types on the same report, they finish it in 3 hours, how long would it take Betty to type the report by herself

Answer 1

R * 4 = 1000; R = 1000 / 4 = 250
(R + B) * 3 = 1000
3R + 3B = 1000,
3B = 1000 - 3R = 1000 - 750 = 250
B = 250/3

t(B) = 1000 / (250/3) = 12 hours