Question

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. (Answer is 1000 how can find it).

Answer 1

Let the total marks of students be 100.

= > Given that in an examination 50% students passed in mathematics.

The number of students failed in maths = 100 - 50

                                                                     = 50%.


= > Given that 70% of students passed in science.

The number of students failed in science = 100 - 70

                                                                       = 30%.


= > Given that 10% of students failed in both subjects.

Total number of students failed in both subjects = 50 + 30 - 10

                                                                                 = 70.


The total number of students passed in both subjects = 100 - 70

                                                                                             = 30%.

Now,

Let the total number of students be x.

= > 30% of (x) = 300

= > (30/100) * x = 300

= > 30x = 30000

= > x = 30000/30

= > x = 1000.


Therefore, the total number of students appeared in the examination = 1000.


Hope this helps!