Math Question

Question

2. There are two No-Cavity bins at a dentist’s office. One bin has two hot-pink toothbrushes and three neon-yellow toothbrushes. The other bin has four packages of sugar-free gum, three grape, and one strawberry. Kira has no cavities. The dentist tells her to close her eyes and choose a prize from each bin.

 

 

b. The dental assistant refills the bins after every patient. Suppose the next 100 patients have no cavities. How many times do you expect the patients to get a neon-yellow toothbrush and a pack of grape gum?

Answer 1

2 pink tb + 3 yellow tb = 5 toothbrushes total, and there are 3 out of 5 yellow.

There are four gum packs available, three of four are grape.

 

3/5 * 3/4 = 9/20 → .45 → 45%

So we should expect 45 people out of 100 to get yellow toothbrushes and grape gum.