The marks obtained by a student of class XI in first terminal and second terminal are 62 and 48 respectively. Find the number of minimum marks he should get in the annual examination to have an average of at least 60 marks.

Ravi obtained 70 and 75 marks in first two unit test. Find the minimum marks he should get in the third test to have an average of at least 60 marks.

The mean marks of boys and girls in an examination are 70 and 73, respectively. If the mean marks of all the studetns in that examinatin is 71, find the ratio of the number of boys to the number of girls.

The marks (out of 100) obtained by a group of students in a science test are 85, 76, 90, 85, 39, 48, 56, 95, 81 and 75. Find the: Range of the marks obtained.

The percentage of marks obtained by a student in the monthly unit tests are given below : Based on this data, find the probability that the student gets more than 70% marks in the next unit test.

The percentage of marks obtained by a student in the monthly unit tests are given below: Based on this data, find the probability that the student gets more than 70% marks in a unit test.

Marks obtained by 2500 students are shown in the following table: A student is selected at random. Find the probability that : he scores less than 60% marks.

Marks obtained by 2500 students are shown in the following table: A student is selected at random. Find the probability that : he scores more than 80% marks.

To receive Grade ‘A’ in a course, one must obtain an average of 90 marks or more in five examinations (each of 100 marks). If Sunita’s marks in first four examinations are 87, 92, 94 and 95, find minimum marks that Sunita must obtain in fifth examination to get grade ‘A’ in the course.

Consider the marks obtained (out of 100 marks) by 30 students of Class IX of a school: Find the mean of the marks obtained by 30 students of Class IX of a school.