Question

A box contains 100 colored chips; some are pink and some are blue. Milton chooses a chip at random, records the color, and places it back in the bag. Milton has recorded 12 pink chips and 18 blue chips. Using these results, what is the predicted number of pink chips in the box?

Answer 1

I will second that answer. It is 40. 12 pink / 30 total known = x / 100. Approximately 3.33 x 30 = 100, so 3.33 x 12 = 39.96 = 40.

Answer 2

The approximate number of pink chips is 40. Here's why: what you need to do is set up the problem as shown below. 12 goes above 30 because you have to know what the total number of chips chosen is in order to relate it to 100 chips. From there, all you have to do is cross-multiply and divide (or my middle school teacher used to call it fish.... I'll explain why). First you are going to draw a line from the 100 to the 12 and multiply them. then you are going to curve the line that you will draw from the 12 to the 30 and divide the product of 12 and 100 by 30. Then you will draw a line from the 30 to the X meaning that the quotient that you find from the product of 120 and 100 divided by 30 equals X. Hope that helps.

12 x
30 100