Question

Carter has a large marble collection. Carter knows that he has exactly 20 blue marbles in his collection, but does not know how many marbles he has in all. Carter mixes up his marbles and randomly selects 40 marbles. Of the 40 marbles that he chose, 4 were blue. How many marbles does Carter have in total? You MUST explain your reasoning

Answer 1

4/40 = 0.1

0.1x = 20

x = 200

Answer 2

ms sue how did you this? did carter multiply the 40 select marbles by the 20 exactly marbles?

Answer 3

Since 4 of 40 marbles were blue, we assume that about 10% of his total marbles are are blue.

10% of 200 is 20.