Correct Answer - Option 4 : None of these
Given:
Average marks of 29 students = 70
Average marks of the first 15 students = 75
Average marks of the last 15 students = 66
Formula Used:
Average = Sum of values/Number of values
Concept Used:
A positive integer that has at least one divisor other than 1 and itself is called a composite number.
Calculation:
Total marks of the first 15 students/15 = 75
⇒ Total marks of the first 15 students = 1125
Total marks of the last 15 students/15 = 66
⇒ Total marks of the last 15 students = 990
Total marks of 29 students/29 = 70
⇒ Total marks of 29 students = 2030
⇒ 1125 + 990 + m = 2030
⇒ 2115 + m = 2030
⇒ m = 85
A. m is not a multiple of 17
85 = 5 × 17
⇒ 85 is a multiple of 17
⇒ A is not correct
B. m/17 is a composite number
85/17 = 5
5 is a prime number, it has only two divisors, 1 and itself.
⇒ B is not correct
C. m = √(m + 15) × 8
√(85 + 15) × 8 = 10 × 8
⇒ 80
≠ m
⇒ C is not correct
D. 2m = 250 – m
2m = 2 × 85
⇒ 170
250 – m = 250 – 85
⇒ 165
≠ 2m
⇒ D is not correct
∴ None of these is correct.
