What is the mark scored by Abhijit in English?
I. Marks scored by Abhijit In Mathematics are more than his marks in Science by 20.
II. Total marks scored by Abhijit in Mathematics, Science and English are 197.
III. Marks scored by Abhijit in Science are more than his marks in English by 12.

From Statement I,
SI = PRT/100
? P = (P x R x 10)/100
? R = 10%


From Statement II,
Difference (D) = PR²/(100)²
? 150 = (15000 x R²)/10000
? R = 10%

Thus, either Statement I or II is sufficient.

(A + B)'s 1 day's work = 1/8 ..........(i)
(B + C)'s 1 day's work = 1/10 ..........(ii)
(C + A)'s 1 day's work = 1/12 ............(iii)
Add the equation (i), (ii), (iii)
2(A + B + c)'s 1 day's work = 1/8 + 1/10 + 1/12
(A + B + C)'s 1 day's work = 1/2[1/8 + 1/10 + 1/12] ..........(iv)
Subtracting Eq. (iii) from Eq. (iv), we get B's 1 day's work.
then, required number of days = 1/(B's 1 day's work) .
So we need all above 3 statements to solve the given question.

Form Statement I,
R A      G E
Clearly , the left place or empty place is filled by N .
From Statement II ,
   A  N  G    
   G   N  A    
Clearly N is at third place ,
Hence, the data in Statement I alone or in Statement II alone are sufficient to answer the question .

From Statement I,
N > M > K
From Statement II ,
L > N
From both the Statement
L > N > M > K
but height of J is not clear .
Thus second tallest friend cannot be determined.
Hence, data neither in Statement I nor in Statement II are sufficient to answer the question .

From Statement I,
Number of student in the class
= 21 or 22 or 23 or 24 or 25 or 26
From Statement II,
Number of student in the class
= 25 or 26 or 27 or 28 or 29 or 30
Sine , number of student can be divided into group of 5 students, therefore number of student must be multiple of 5.
? NUmber of student in the class = 25 or 30
Combining Statement I and II .
Number of Student in the class = 25
Hence , the data in both the Statement I and II together are necessary to answer the question .

(X + Y)'s 1 day's work = 1/8       ..(i)
(Y + Z)'s 1 day's work = 1/10    ...(ii)
(Z + X)'s 1 day's work = 1/12    ..(iii)
Adding equations i , ii , iii
2(X + Y + Z)'s 1 day's work = 1/8 + 1/10 + 1/12
(X + Y + Z)'s 1 day's work
= 1/2[1/8 + 1/10 + 1/12]    ..(iv)
Subtracting Eq. (iii) from Eq. (iv), we get Y's 1 day's work,
Then, required number of days
= 1/Y's 1 day's work

Data are not sufficient even from Statement I and II both.

From Statement I,
R = (SI x 100) / (P x T)
? (1736 x 100)/(6200 x 2) = 14%

From Statement II,
1348.2 4500(1 + r/100)² - 4500
? 1348.2 + 4500 = 4500(1 + r/100)²
? 5848.2 = 4500((1 + r/100)²
? 5848.2/4500 = (1 + r/100)²
? 3249/2500 = (1 + r/100)²
? (57/50)² = (1 + r/100)²
? 1 + r/100 = 57/50
? r/100 = 57/50 - 1 = 7/50
? r = 7 x 100/50
? r = 14%

Both statement are alone sufficient.

Data given in Statement I alone are sufficient to answer the question

We know that,
Speed of boat in still water
= (Speed upstream + Speed downstream)/2
From Statements I and II,
Speed = (6 + 4)/2 = 10/2 = 5 km/h
So, answer can be determined from both statements.