Question

Mack's Toy Shop made 600 trains yesterday and found that 30 were defective. They

plan to make 4,500 trains this week.

Using the information given, how many trains are expected to be defective?

225 trains

6,000 trains

15 trains

500 trains

Answer 1

225 trains

Explanation:

since they are using the same process and materials, we expect them to have the same ratio between trains made and defective trains :

600 / 30 = 20/1

one out of 20 is defect.

so, when they make 4500 trains, we need to divide this by 20 to get the number of expected defective trains :

4500 / 20 = 225

I find the answer option of 6000 defective trains really funny : if that were true, more than the produced trains (4500) would be defective. how ... ?