Liwana spent 2 2/5 hours on his math homework and 1 3/5 hours on his science homework. How much time did he spend doing math and science homework?

Answer 1

To find out how much time Liwana spent doing math and science homework, we need to add the time she spent on each subject.

Liwana spent 2 2/5 hours on math, which can also be written as 12/5 hours.
Liwana spent 1 3/5 hours on science, which can also be written as 8/5 hours.

So, Liwana spent 12/5 + 8/5 = 20/5 = 4 hours doing math and science homework. Answer: \boxed{4}.