Question

In a particular lottery, 5 winning numbers are drawn from a set of 37 numbers. What is the probability of picking exactly 2 of the winning numbers in this lottery? Round your answer to the nearest
thousandth (three decimal places).

Answer 1

Since 5 winning numbers are draw and there are exactly 2 winning numbers, the other 3 numbers chosen have to be incorrect.

The 2 numbers picked right, there are 5C2=10 different possibilities.

The other 3 numbers are just picked from the rest of the 32 numbers. Getting there are 32C3=4960 different possibilities.

For each set of 2 correct winning numbers, you could have the 4960 different losing numbers to match up to make a unique set. This meant that there are 4690*10=46900 different total possibilities.

Now the total different outcomes of how you can choose the numbers are 37C5=435897 outcomes.

Now the way to find probabilities is want/total

The want is 46900 and the total is 435897

Doing the division you get the number rounded to the nearest thousandths as   0.107 or in percent form as

10.759% chance of picking exactly 2 winning numbers.

This seems like a competition problem of some sort therefore I assume that you already know what combinations in form nCk and permutation in form nPk means.