What is the difference between the marks obtained by C and F ........

Logial Reasoning (CLAT) Puzzle Test

Directions : Study the following information carefully and answer the given below.

Six students A, B, C, D, E and F wrote an exam and the following is the data regarding their marks (maximum marks is 20).
E got twice as much as A.
A got one-and-a-half times as much as C.
B got one-third of the marks scored by E.
D got double that of C.
F scored 6 marks more than A but is not the topper of the class. (All marks are integers)

What is the difference between the marks obtained by C and F?

Explanation:

Let's A is x
E is 2x
C is 2x/3
B is 2x/3
D is 4x/3
F = x+6
Let's choose the option to find the value of E (only E can be topper, because he got twice marks as A)
if we choose, E = 12 then,
A = 6, C = 4, B = 4, D = 8, F = 12
In this case, value of E and F are same,
but, there is only one topper.
Hence, value of E = 18 and he is the topper.
If, the value of E is 18, then, the value of A is 9.
Value of C = 2x/3 = 2(9)/3 = 6
Value of F = x + 6 = 9 + 6 = 15
F - C = 15 - 6= 9