Ravi and Kumar are working on an assignment. Ravi takes 6 hours to type 32 pages on a computer, while Kumar takes 5 hours to type 40 pages. How much time will they take, working together on two different computers to type an assignment of 110 pages?
7 hours 30 minutes
8 hours
8 hours 15 minutes
8 hours 25 minutes
Explanation:
Number of pages typed by Ravi in 1 hour =$ \dfrac{32}{6} $=$ \dfrac{16}{3} $.
Number of pages typed by Kumar in 1 hour =$ \dfrac{40}{5} $= 8.
Number of pages typed by both in 1 hour =$ \left(\dfrac{16}{3} + 8\right) $=$ \dfrac{40}{3} $.
Time taken by both to type 110 pages =$ \left(110 \times\dfrac{3}{40} \right) $hours
= 8$ \dfrac{1}{4} $hours [or] 8 hours 15 minutes.