Help someone tell me how to figure out these i forgot

Naomi’s parents want to have 50,000, saved for her college education, if they invest 20000 today and earn 7% interest compound annually, about how long will it take them to save 50 thousand

To make a monster appear large in a movie, a human actor wore a costume and walked through a scale model of a city. the scale used was 1 inch = 15 feet. the actor is 60 inches tall. how tall does the monster appear in the movie? question 5 options: 720 feet 75 feet 4 feet 900 feet

Parks is wearing several rubber bracelets one third of the bracelets are tie dye 1/6 are blue and 1/3 of the remainder are camouflage if park swears to camouflage bracelets how many bracelets does he have on