Question

Amar wrote exams in four subjects - Physics, Chemistry, Biology and Social Studies. The ratio of marks he got in these exams was 2 : 3 : 4 : 5. He got an aggregate of 70% in these exams. Each exam had the same maximum marks. In how many of these exams did he get more than 50%. ?

Answer 1

Let the maximum marks of each subject = y
Let the marks scored in Physics, Chemistry, Biology and Social studies be 2x, 3x, 4x and 5x.Now, total marks scored in all 4 subjects = 2x + 3x + 4x + 5x = 14x
Total maximum marks of all 4 subjects = 4y
Now, according to question :    (14x/4y×100)% = 70%⇒14x/4y×100 = 70
⇒y = 5x
%age of marks scored in Physics = (2x/5x×100)% = 40%
%age of marks scored in Chemistry = (3x/5x×100)% = 60%
%age of marks scored in Biology = (4x/5x×100)% = 80%
%age of marks scored in Social Studies = (5x/5x×100)% = 100%
So, he got more than 50% in Chemistry, Biology and Social Studies.