Question

In a new lottery game, contestants pick 5 numbers (1-9 inclusive) and must guess exactly 3 correct in order to win. What’s the probability of winning this lottery?

Answer 1

Answer: 0.6%

Step-by-step explanation:

We have a selection of 5 numbers, in those selection we have 3 combinations of 3 consecuitve numbers (because the numbers must be in correct order).

The first 3

The 3 in the middle

the last 3.

So a contestant has 3 combinations were he wins.

Now, the number of possible combinations of the 9 numbers given is:

For the first number we have 9 options.

For the second number we have 8 options (because we already selected one)

For the last number we have 7 options (because we already selected 2 numbers)

Then the number of possible combinations is

10*9*8 = 504

The probabilty of winning will be equal to the number of combinations that the contestant has (3) divided by the total number of combinations, this is:

p = 3/504 = 0.006 or 0.006*100% = 0.6%