According to question ,
Difference = 83 – 53 = 30
Incorrect observation > Correct observation

Correct Option: B

According to question ,
Difference = 83 – 53 = 30
Incorrect observation > Correct observation

Number of successful students in the exam = p
∴ Number of unsuccessful students = 100 – p
According to the question,

Correct Option: C

According to the question,

B’s weight = (A + B)’s weight + (B + C)’s weight – (A + B + C)’s weight
B’s weight = (40 × 2 + 2 × 43 – 45 × 3) kg.
B’s weight = (80 + 86 – 135) kg.

Correct Option: A

B’s weight = (A + B)’s weight + (B + C)’s weight – (A + B + C)’s weight
B’s weight = (40 × 2 + 2 × 43 – 45 × 3) kg.
B’s weight = (80 + 86 – 135) kg.
B’s weight = 31 kg.

Here , The average of 25 results = 20.
The average of first 12 results = 15
and average of the last 12 results = 18.
Value of 13th result = 25 × 20 – 12 × 15 – 12 × 18

Correct Option: C

Here , The average of 25 results = 20.
The average of first 12 results = 15
and average of the last 12 results = 18.
Value of 13th result = 25 × 20 – 12 × 15 – 12 × 18
Value of 13th result = 500 – 180 – 216
Hence , Value of 13th result = 104

Let average marks of remaining 30 students be p.

Correct Option: B

Let average marks of remaining 30 students be p.