Katie has 13 pink marbles. She has 9 fewer orange marbles than pink marbles. She has 4 times as many purple marbles as orange marbles. How many marbles does Katie have in all?
Work out the solution step by step. 
Find the number of orange marbles. 13 marbles - 9 marbles = 4 marbles
Find the number of purple marbles. 4 marbles x 4 = 16marbles
Find the total amount of pink, orange, and purple marbles. 13 marbles + 4 marbles + 16 marbles = 45 marbles