Joan has 45 marbles . mary has m marbles if joan has 15 times as many marbles , write an equation that shows how many marbles mary has

Let's rewrite the question correctly:
 
 Joan you have 45 marbles. MARY HAS m marbles if Joan has 15 times as many marbles AS MARY, write an equation that shows how many marbles mary has
 For this case, what we are going to do is write a step-by-step equation to find the correct expression.
 "Joan has 45 marbles"
 45
 "MARY HAS m marbles"
 m
 Joan has 15 times as many marbles as mary
 45 = 15m
 We clear m:
 m = 45/15 = 3
 Mary has 3 marbles.
 
 an equation that shows how many marbles mary has is:
 45 = 15m