in an examination 50% of the studentspassedin mathematics and 70% of studentspassed in science while 10 % students failed in both subjects .300 students passed in at leastone subject .find total number of students who appeared in the examination if they took examination in only twosubjects.

see the related questions below.

To find the total number of students who appeared in the examination if they took the examination in only two subjects, we can use the principle of inclusion-exclusion.

Let's assume the number of students who appeared in the examination is "x".

According to the given information:
- 50% of students passed in mathematics, which means 0.5x students passed in mathematics.
- 70% of students passed in science, which means 0.7x students passed in science.
- 10% of students failed in both subjects, which means (0.1x) students failed in both subjects.

Now, let's calculate the number of students who passed in at least one subject:
- The total number of students who passed in mathematics or science is the sum of those who passed in mathematics and those who passed in science, but we need to subtract the number of students who passed in both subjects as we counted them twice.
- So, the number of students who passed in at least one subject is (0.5x + 0.7x - 0.1x).

Given that 300 students passed in at least one subject, we can write the equation:

0.5x + 0.7x - 0.1x = 300

Simplifying the equation:

1.1x = 300

Dividing both sides by 1.1:

x = 300 / 1.1

x ≈ 272.73

Since the number of students must be a whole number, the closest whole number approximation is 273.

Therefore, the total number of students who appeared in the examination if they took the examination in only two subjects is 273.