Combinatorics

Answer all the questions below and press submit to see how many you got right.

id: 14488

In a set of 39 numbers 15 numbers are divisible by 2, 12 are divisible by 3 and 20 are neither divisible by 2 or by 3. How many numbers in the set are divisible by 6?

id: 14612

In a restaurant the guests can choose a main out of 4 pizzas and 5 pastas. How many main courses are there?

id: 14581

In a special deal of a restaurant you can get a discount if you order a meal consisting out of one of 2 appetizers, one of 2 main courses and one of 5 deserts. How many different meals can you order?