There are 15 purple marbles, 3 pink marbles and 12 gray marbles. What is the ratio of purple marbles to all marbles?

The volume of a sphere is increased by 6%. calculate the corresponding percentage increased in it area.

Logan wants to know how many skateboards have defective parts. he inspects 20,000 skateboards and keeps track of the number of defects per board. use his probability distribution table to find the expected value for defects on a skateboard.

Pepe and leo deposits money into their savings account at the end of the month the table shows the account balances. if there pattern of savings continue and neither earns interest nor withdraw any of the money , how will the balance compare after a very long time ?