One pipe can fill a tank in 6 hours and another pipe can fill the tank in 10 hours. how long will it take to fill the tank if both pipes are used?

What are the domain and range of the function f(x)=2^x+1

The anwser cause i do not understand just plez

Abag contains pieces of paper numbered from 5 to 9. a piece of paper is drawn at random. what is the theoretical probability of drawing a number less than 8?