Three years back, a father was 24 years older than his son. At present the father is 5 times as old as the son. Write an equation to represent this situation.

  5s -3 = s -3 + 24    5s -3 = s + 21

Step-by-step explanation:

Father   f

Son   s .   present:  f = 5s  use this equation to substitute the equal value

3 years ago .  f-3 = s-3 + 24  

Substitute 5s for f in the second equation

5s -3 = s-3 + 24

works out as  5s -s = - 3  +3 + 24

4s = 24  

4s/4 = 24/4  

s = 6

The son's age is 6, The father is 30

the answer is 15% decrease

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.