In a batch of 890 calculators, 12 were found to be defective. What is the probability that a calculator chosen at random will be defective?

1 Answer
Sep 17, 2016

The probability of choosing a defective calculator at random would be 12/890 (or ~~1.35%).

Explanation:

The reason why the probability of choosing a defective calculator is 12/890 is because as stated in the problem, 12 calculators would be defective out of 890, thus the ratio would be 12 to 890.

Note: Some people might want to simplify the fraction, however if you simplify 12/890 into 6/445 then you not would be telling the whole story.

Finally, to get 1.35% you can write the following proportion.

12/890=x/100

Multiply 12 by 100 and 890 by x. After that you should get the following:

890x=1200 Divide by 890

x=1.3483146057413033707...