Discussion

Explanation:

Arranging marks in descending order

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Difference in marks between consecutively ranked students:
E – C = 5
H – E = 10
B – H = 9
F – B = 5
D – F = 15
G – D = 6
A – G = 10

Since rank of all students changed after adding marks of LRDI section, hence C who had least marks in Quant section will not have least overall marks.
⇒ C will definitely get non-zero marks in LRDI section.

If exactly 2 students scored non-zero in LRDI one of the two will be C.

Difference in marks of D and F is highest. Hence, if C get 30 marks in LRDI he will move above F in ranking, while ranks of F, B, H and E will slip by 1 position.

Now we are left with A, G and D. 

If D gets 17 marks in LRDI, he will move above A in raking while ranks of A and G will slip by 1 position.

Total marks after above changes.

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Now, ranks of none of the students is same as that earlier while all of them have different total marks.

∴ Least total marks scored in LRDI section by all students = 30 + 17 = 47.

Hence, 47.

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