sorry,but I don't understand word problems - like what formula/expression to use. Here's the 1st problem: Rob practiced 3/5 of his music in 25minutes. About how long does it take to practice all of his music?

I know that Rob has 2/5 left of music to practice. So, do I multiply 2/5 by 25minutes?

Here's the 2nd problem: Jared vowed to walk 100miles a month. If he can walk 1/2mile in 20minutes, how many minutes will it take him to walk 100miles?

In this case, do i multiply 100 by 1/2, then multiply by 20minutes?