The question is not clearly stated, but I will try to answer it.
The problem is: "Can a pizza have more than one identical topping?"
- If there can be more than one identical topping, then the number of ways can be calculated as:
The number comes from multiplying number of cheese types, and the number of toppings (3 times)
- if the toppings cannot be different, then the number is:
The number is calculated as follows:
cheese can be chosen in 4 ways,
the first topping can be chosen in 10 ways
the second topping can be chosen in 9 ways (it cannot be the same as the first one)
the third topping can be chosen in 8 ways (it cannot be the same as the first and the second one)
Hope that helps.