In a medical institute, the strength of the students in the first two classes are in the ratio of 8:7. The ratio of the number of students in the second and the third classes is 2:3. What is the average of the number of students in the first and third classes, if the number of student is the second class is 612?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 808.71.
Class 1 : Class 2 = 8 × 2 : 7 × 2 = 16 : 14
Class 2 : Class 3 = 2 × 7 : 3 × 7 = 14 : 21
Class 1 : Class 2 : Class 3 = 16 : 14 : 21
Ratio total for Class 2 = 14 units = 612 students
So, 1 unit = 612/14 = 43.714
Class 1 = 16 × 43.714 ≈ 699.43
Class 3 = 21 × 43.714 ≈ 917.99
Average = (699.43 + 917.99)/2 = 1617.42/2 = 808.71 or 809