Kim started to nap at 115 and woke at 144, what is the number of minutes she napped

Kim started to nap at 115 and woke up at 144.

Let's find the number of minutes that she napped.

I believe this is 1:15 not 115 because there's no such time.

Same goes with 144, its 1:44 and not 144.

Now, to be able to get the number of minutes that Kim napped,

Simply subtract the time she woke up by the time she started to take a nap

.=> 1:44 - 1: 15

=> 29 minutes is the number of minutes that Kim napped.