Question

Suppose that 1000 seven-digit telephone numbers within your area code are dialed randomly. What is the probability that a dialed number starts with the digit 9?

1) 0.1
2) 0.9
3) 0.01
4) 0.001

Answer 1

1) 0.1

The probability that a randomly dialed seven-digit telephone number within an area code starts with the digit 9 is 0.1.

Step-by-step explanation:

The probability that a dialed number starts with the digit 9 is determined by the fact that there are 10 possible digits (0-9) that could start a telephone number, assuming that a telephone number can start with any digit and that each digit has an equal likelihood of being chosen.

The probability is therefore 1 out of 10, or 0.1, since only one digit out of the ten possible digits is desired.