 Hello students, let's solve the following question of probability. It says in class 11th of a school 40% of the students study mathematics 30% study biology 10% of the class study both mathematics and biology. If a student is selected at random from the class Find the probability that he will be studying mathematics or biology Let us now start the solution and let a be the number of students studying mathematics B be the number of students studying biology Now we have given that 40% of the students study mathematics So the probability of a is 40% which can be written as 40 upon 100 which is equal to 0.40 and probability of B is 30% Which is equal to 0.30 Now we are given that 10% of the students study both mathematics and biology so the probability of a and B or we can say probability of a intersection B is 10% which is equal to 0.10 We have to find the probability of a student which is selected at random studying mathematics or biology So we have to find probability of a or B or we can say probability of a union B Now we know that probability of a or B is given by probability of a plus probability of B minus probability of a and B Now probability of a is 0.40 probability of B is 0.30 and probability of a and B is 0.10 Which is equal to 0.60 So the probability of a student who is studying mathematics or biology is 0.60 which is same as 0.6 It's a question and the session. Bye for now. Take care. Have a good day