A fuel injection system is designed to last 18 years, with a standard deviation of 1.4 years. What is the probability that a fuel injection system will last less than 15 years?

1.6%.

Step-by-step explanation:

Assuming a Normal Distribution the z score is (x - m) / s

where m = mean and s = the standard deviation.

So it is 15-18 / 1.4

= - 2.1429.

From the Normal Distribution tables we see that this corresponds to a probability of 0.016.

As a percentage this is 1.6 %.