Question

A two-digit locker combination has two nonzero digits and no digit is repeated in any combination.

Answer 1

Answer:

Answer choice C

Step-by-step explanation:

Similarly to the previous problem, there are two possibilities. In the first possibility, the chance of picking a digit lower than 7 is 6/9 or 2/3, because there are 6 digits below 7 and 9 digits in total. In this scenario, the probability of the second digit being below 7 is 5/8, since one of the digits has already been taken. The probability here is 5/8*6/9=5/12. In the other scenario, the probability of picking a number higher than 7 is 3/9 or 1/3. In this scenario, the probability of picking below 7 for the second digit is 6/8 or 3/4, because one of the digits has not been taken. 3/9*6/8= 1/4. Adding these two together, you get 8/12=2/3, or answer choice C. Hope this helps!