Answer: Option B

Explanation:
Total marks obtained by a class of 25 students
                                             = 3*95 + 3*0 + 19 * 45 =1140
Average marks of whole class = 1140/25 =45.6  

Answer: Option B

Explanation:
Total marks obtained by a class of 25 students
                                             = 3*95 + 3*0 + 19 * 45 =1140
Average marks of whole class = 1140/25 =45.6  

Answer: Option C

Explanation:
Average daily expenditure
= Total expenditure / no. of days
= 31*12 + 30*14 + 31*17/92
= 14.33      

Answer: Option A

Explanation:
Runs scored in the first 10 overs = 10 × 3.2 = 32
Total runs = 282
Remaining runs to be scored = 282 - 32 = 250
Remaining overs = 40
Run rate needed = 250/40 = 6.25

Answer: Option B

Explanation:

Let the sale in the sixth month =x
Then (6435+6927+6855+7230+6562+x)/6 = 6500
=> 6435 + 6927 + 6855 + 7230 + 6562 + x  = 6 × 6500
=> 34009 + x = 39000
=> x=39000 − 34009 = 4991
 

Answer: Option C

Explanation:
Let Madan's weight = x. Then
According to Madan, 65 According to brother, 60 According to mother, x ≤ 68 ----(equation 3)
Given that equation 1,equation 2 and equation 3 are correct. By combining these equations,we can write as
65 i.e., x = 66 or 67 or 68
Average of different probable weights of Madan = (66+67+68)/3 = 67

Answer: Option B

Explanation:
Let the total number of students = x
The average marks increased by 1/2 due to an increase of 83 - 63 = 20 marks.
But total increase in the marks = 1/2 × x = x/2
Hence we can write as
x/2 = 20
⇒ x = 20 × 2 = 40

Answer: Option A

Explanation:
Let the number of workers = x
Given that average salary of all the workers = Rs.8000
Then, total salary of all workers = 8000x
Given that average salary of 7 technicians is Rs.12000
=> Total salary of 7 technicians = 7 × 12000 = 84000
Count of the rest of the employees = (x - 7)
Average salary of the rest of the employees = Rs.6000
Total salary of the rest of the employees = (x - 7)(6000)
8000x = 84000 + (x - 7)(6000)
=> 8x = 84 + (x - 7)(6)
=> 8x = 84 + 6x - 42
=> 2x = 42
=> x = 42/2 = 21

Answer: Option C

Explanation:
Let the number of subjects = x
Then, total marks he scored for all subjects = 63x
If he had obtained 20 more marks for his Geography and 2 more marks for his history, his average would have been 65
=> Total marks he would have scored for all subjects = 65x
Now we can form the equation as 65x - 63x = additional marks of the student = 20 + 2 = 22
=> 2x = 22
=> x = 22/2 = 11

Answer: Option A

Explanation:
Total age of husband and wife (at the time of their marriage) = 2 × 23 = 46
Total age of husband and wife after 5 years + Age of the 1 year old child 
= 46 + 5 + 5 + 1 = 57
Average age of the family = 57/3 = 19