If a restaurant offers 10 different toppings for its pizzas, and a customer chooses exactly 3 toppings for their pizza, how many possible topping combinations can the customer choose?

Instruction: Calculate the number of ways to choose 3 toppings out of 10 without regard to the order.

Context: This question assesses the candidate's understanding of combinations and their application in creating menu options.

Official Answer

Certainly! To solve this question, we're looking at a classic example of a combination problem from combinatorics, a fundamental concept that's not just academic but has real-world applications, especially in fields like data science and software engineering where I have honed my skills. When we talk about combinations, we're focused on selecting items where the order does not matter. This is crucial in situations like this pizza topping question, where selecting onions, peppers, and mushrooms is the same combination as choosing mushrooms, onions, and peppers.

To calculate the number of possible combinations of 3 toppings out of 10, we use the combination formula which is (C(n, k) = \frac{n!}{k!(n-k)!}), where (n) is the total number of items to pick from, (k) is the number of items to pick, and (n!) denotes the factorial of (n), which is the product of all positive integers up to (n).

In our case, (n=10) because we have 10 toppings to choose from, and (k=3) because the customer chooses exactly 3 toppings. Plugging these values into our formula gives us:

(C(10, 3) = \frac{10!}{3!(10-3)!} = \frac{10!}{3!7!})

Calculating the factorials, we find:

(10! = 10 \times 9 \times 8 \times 7!) and since (7!) appears on both the numerator and denominator, they cancel out. This leaves us with (10 \times 9 \times 8) in the numerator and (3! = 3 \times 2 \times 1) in the denominator.

Simplifying this:

(C(10, 3) = \frac{10 \times 9 \times 8}{3 \times 2 \times 1} = \frac{720}{6} = 120)

Therefore, there are 120 possible combinations of 3 toppings from a selection of 10.

This approach to problem-solving is indicative of how I tackle challenges in my career. Whether it's optimizing a data algorithm as a Data Scientist, refining a machine learning model, or analyzing complex data sets, breaking down the problem into manageable parts and applying mathematical principles, ensures accuracy and efficiency. Furthermore, this methodology is adaptable and can be modified based on the specifics of the problem, making it a powerful tool in my professional toolkit. This flexibility and precision have been key components of my success across various projects, from designing predictive models to analyzing user behavior data to enhance product features.

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