In class XI of a school 40% of the students study Mathematics and 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 or both.

A class has 12 boys and 4 girls. If three students are selected at random from the class, what is the probability that all will be boys?

In a class of 60 students, 30 opted for Mathematics, 32 opted for Biology and 24 opted for both Mathematics and Biology. If one of these students is selected at random, find the probability that : (i) The students opted for Mathematics or Biology. (i) The students has opted neither Mathematics nor Biology. (iii) The students has opted Mathematics but not Biology.

A class has 20 girls and 16 boys. One student is selected at random. Find the probability that the student is a girl.

In a school 25% students are failed in Mathematics, 15% in Physics and 5% students fail in both Mathematics and Physics. A student is selected at random. (i) If he is fail in Physics, find the probability that he is fail in Mathematics. (ii) If he is fail in Mathematics, find the probability that he in fail in Physics. (iii) Find the probability that he is fail either in Mathematics or in Physics.

There are 60% students in Maths and 30% in Biology. If 10% students are in both subjects. Find the probability that a randomly selected student has Maths or Biology.

In a class, 5% of the boys and 10% of the girls have an IQ of more than 150. In this class 60% of the students are boys. If a student is selected at random and found to have an IQ of more than 150, find the probability that the student is a boy.

In a medical examination of students of a class, the following blood groups are recorded. A student is selected at random from the class. The probability that he/she has blood group B, is

In a class of 50 students, 20 are boys and rest are girls. A student is selected at random. Find the probability of selecting a boy.

A class consists of 50 students out of which there are 10 girls. In the class 2 girls and 5 boys are rank holders in an examination. If a student is selected at random from the class and is found to be a rank holder, what is the probability that the student selected is a girl?

In a class of 125 students 70 passed in Mathematics, 55 in statistics, and 30 in both. Then find the probability that a student selected at random from the class has passed in only one subject.