2016 AMC 10B Problem 12

Attempt Problem 12 of the 2016 AMC 10B below, then check your answer against the professionally curated solution from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2016 AMC 10B solutions, or check the answer key.

All problems are used with official legal permission of the Mathematical Association of America (MAA).

12.

Two different numbers are selected at random from {1,2,3,4,5}\{1, 2, 3, 4, 5\} and multiplied together. What is the probability that the product is even?

 0.2 \ 0.2

 0.4 \ 0.4

 0.5 \ 0.5

 0.7 \ 0.7

 0.8 \ 0.8

Answer: D
Concepts:basic probabilitycomplementary countingparity
Difficulty rating: 960
Solution:

The product is odd if and only if both numbers are odd. There are (32)=3\binom 32=3 ways to do this out of a possible (52)=10\binom 52=10 ways. This makes the probability of it being odd equal to 310=0.3.\frac 3{10} = 0.3. This means the probability it is even is 10.3=0.7.1-0.3=0.7.

Thus, the correct answer is D .

← Problem 11#11
Full Exam

Problem 12 in Other Years