A student's average marks in five subjects is 82. If the average marks of first two subject is 86.5 and the average marks of last two subjects is 84. Find the marks of third subject?

Correct Answer: 69

The total marks of all 5 subjects = 82 x 5 = 410

Total marks of 1st two subjects = 86.5 x 2 = 173

Total marksĀ of last two subjects = 84 x 2 = 168

Now, marks in 3rd subject = 410 - (173 + 168) = 410 - 341 = 69.