Can someone solve this please?

Present age of man is 45 years, 5 years back his age was 4 times age of his son what is present age of his son?

Jo divides a candy bar into eight equal pieces for her children to share she gives three pieces to sam three pieces to leslie and two pieces to margie rose the two month old baby does it doesn't get any what fraction shows how muchw candy each of the four children got. what's the answer to my question

If the average of x,y and z is 15 what is their sum