Question

In an elementary school classroom, two students are given the task of cleaning the chalkboard. The first student can clean it by himself in one minute, while the other student takes 20 seconds longer. Which of the following equations can be used to determine how many seconds it would take for both students to clean the chalkboard if they work together?

Answer 1

Answer:

I think it's 1/60 + 1/20 = 1/x Thats what I put. Let me know if it works :)

Answer 2

Answer:

a minute twenty seconds