Use the subway train schedule below to answer the question.
I Train Schedule I
I Train Arrives Every... I
I Red line 4 minutes I
I Blue line 5 minutes I
I Yellow line 6 minutes I

All three trains just arrived at the station. When will they next all arrive at the station at the same time?

They will all arrive at the station in HOW MANY minutes.

40 minutes

Step-by-step explanation:

The least common multiple of 8 minutes and 10 minutes is ...

 LCM(8, 10) = 8·10/GCD(8, 10) = 80/2 = 40

The red and blue trains will arrive together again in 40 minutes

take the top number and divide it by a the bottom number

step-by-step explanation:

1/2 1 divied by 2 = .5

a) one student is chosen from classroom a, then a student is chosen from classroom b.  

step-by-step explanation:

independent events are ones in which the probability of one event does not affect the probability of the second event.

one student is chosen from classroom a; this does not affect the chances of choosing a student from classroom b.   this makes these independent events.

when one card is chosen from a standard deck and then set aside before a second card is chosen, the probability of the second card being chosen changes.   this makes them dependent events.

when one student is chosen from classroom a and then a second student is chosen from classroom a, the probability of choosing the second student changes.   this makes them dependent events.

when a letter is chosen from the alphabet and then a second letter is chosen, the probability of choosing the second letter changes.   this makes them dependent events.