Choose the One Alternative That Best Completes the Statement or Answers

question 517

Multiple Choice

Choose the one alternative that best completes the statement or answers the question.
Solve the problem.
-Between 7:00 AM and 8:00 AM, trains arrive at a subway station at a rate of 15 trains per hour (0.25 trains per minute) . The following formula from statistics can be used to determine the probability that a train will arrive within t
Minutes of 7:00 AM. $$F ( t ) = 1 - e ^ { - 0.25 t }$$ Determine how many minutes are needed for the probability to reach 20%.

• A) \(0.89 \mathrm {~min}\)
• B) \(2.35 \mathrm {~min}\)
• C) \(5.34 \mathrm {~min}\)
• D) \(4.12 \mathrm {~min}\)

---

Definitions:

Background Radiation

This refers to the omnipresent radiation from environmental sources, including cosmic rays and radioactivity from natural materials.

Radon

A radioactive noble gas with the symbol Rn, emanating from the decay of uranium and thorium, posing health risks due to its ionizing radiation.

Radon Gas

Radon gas is a radioactive noble gas that is colorless, tasteless, and odorless, derived from the natural decay of uranium in soil, rock, and water.

Natural Source

An origin of materials or energy that is found in nature and not artificially created, such as sunlight, plants, minerals, or water.