'Twice a number n decreased by five'.

2x-5 is twice a number decreased by 5.

Step-by-step explanation:

2n-5

Step by step Explanation:

You must put 2 in front of "n" to represent the multiplication of the 2 numbers. Then put a subtraction sign and five the show the number is decreased by 5.

Hope this helps!

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.