n a class of 150 students, 50 students passed in mathematics, 40 students failed only in chemistry and 20 students failed in both the subjects. How many students failed in at least one of the subjects?Choices:- 130 125 145 140

To solve this problem, we need to understand that students who failed in at least one subject include those who failed in mathematics, those who failed in chemistry, and those who failed in both.

1. First, let's find out how many students failed in mathematics. Since 50 students passed in mathematics, the number of students who failed in mathematics is 150 (total students) - 50 (passed in mathematics) = 100 students.

2. Next, we know that 40 students failed only in chemistry.

3. We also know that 20 students failed in both subjects.

4. Therefore, the total number of students who failed in at least one subject is the sum of the students who failed in mathematics, those who failed only in chemistry, and those who failed in both.

So, 100 (failed in mathematics) + 40 (failed only in chemistry) + 20 (failed in both) = 160.

However, we have counted the 20 students who failed in both subjects twice (once in the mathematics failure and once in the chemistry failure). So, we need to subtract these 20 students from our total.

Therefore, the total number of students who failed in at least one subject is 160 - 20 = 140 students.

So, the correct answer is 140.