

Hence, the ice-cream flavors can be selected in 792 ways. Use the following formula to get the number of arrangements in which the five ice-cream flavors can be chosen. The number of ice-cream flavors to be selected = r = 5

Total number of ice-cream flavors = n = 8 One ice-cream flavor can be selected multiple times. The order in which the flavors can be selected does not matter in this case. In how many ways can we choose five flavors out of these eight flavors? Solution There are eight different ice-cream flavors in the ice-cream shop. Hence, the pool balls can be selected in 70 different ways. Substitute these values in the above formula: Use the following formula to get the number of arrangements in which the four pool balls can be chosen. The number of balls to be selected = r = 4 The order in which the balls can be selected does not matter in this case. In how many ways can we choose four pool balls? Solution We will now solve some of the examples related to combinations with repetition which will make the whole concept more clear. R = number of elements that can be selected from a set

Here, n = total number of elements in a set You can use the formula below to find out the number of combinations when repetition is allowed. The order does not matter, and flavors can be repeated. In this case, the examples of variations can be:Ĭhocolate, chocolate, vanilla chocolate, chocolate pineapple, etc. Well, if the person can select two scoops at a time, then he can have one flavor two times. What will be the variations in this case? A person can have only two scoops of ice cream. These flavors are chocolate, vanilla, and pineapple. Three flavors of ice-cream are available in an ice-cream cafe. You can see that most of the alphabets are repeated more than once. Ppp, ppq, ppr, pps, pqq, pqr, pqs, prr, prs, pss, qqq, qqr, qqs, qrr, qrs, qss, rrr, rrs,rss, sss For instance, we can make combinations of three elements of the set in this way: This is known as a combination with repetition. We are asked to select q elements from this set, given that each element can be selected multiple times. Let suppose there are p elements in a set A. In this article, we will only discuss the combination with repetition. Like permutation, the combination is of two types: Whereas, the order of arrangements matters in the permutation. However, there is one difference between the two terms and that is the combination deals with counting the number of arrangements in which an event can occur, given that the order of arrangements does not matter. Both these concepts are used to enumerate the number of orders in which the things can happen. There are two main concepts of combinatorics - combination, and permutation. Some notable mathematicians who worked in this field are Blaise Pascal, Leonhard Euler, and Jacob Bernoulli. The interest in the subject reached its peak during the 19th and 20th centuries. Indian, Arabian, and Greek mathematicians are the pioneers of combinatorics. In other words, we can say that it deals with the counting of the number of arrangements in which something can happen. Combinatorics is all about counting, therefore while solving the problems related to combinatorics you will deal with the enumeration of things.

We use the term combinatorics to describe the humungous subset of discrete mathematics that also encompasses graph theory. A branch of mathematics that deals with the counting, combination, and permutations of elements in a set is known as combinatorics.
