Answer:
800 M &Ms
Step-by-step explanation:
First, we can operate on the estimate that the proportion of M&Ms of the sample is equal to the proportion of M&Ms in the giant bag.
Therefore,
number of orange M&Ms in sample / sample size = number of orange M&Ms in bag / bag size
3/50 = 48 / bag size
multiply both sides by 50 to remove a denominator
3 = 48 * 50 / bag size
multiply both sides by bag size to remove the other denominator
3 * bag size = 48 * 50
divide both sides by 3 to isolate bag size
bag size = 48 * 50 / 3
bag size = 800 M &Ms