Answer: Option D. -> none of these

Answer: Option B. -> 640

Answer: Option A. -> 48 Years

Answer: Option B. -> 48 km. per hr.
To find the average speed of the car, we can use the formula:
Average speed = Total distance / Total time
Here, the total distance covered by the car is the sum of the distances covered in the four hours:
Total distance = 52 + 60 + 54 + 26 = 192 km
The total time taken by the car is four hours, since each distance is given for one hour:
Total time = 1 + 1 + 1 + 1 = 4 hours
Using the formula, we get:
Average speed = 192 km / 4 hours = 48 km/hour
Therefore, the correct option is B. 48 km/hour.
Some relevant definitions and formulas to note:

• Speed is defined as the distance covered by an object in a given time. It is usually measured in kilometers per hour (km/h) or meters per second (m/s).
• Average speed is the total distance covered by an object divided by the total time taken to cover that distance.
• Distance is the total length of the path traveled by an object.
• Time is the duration for which an object has been in motion.
• The formula for average speed is Average speed = Total distance / Total time.

In this problem, we were given the distances covered by the car in each hour and asked to find the average speed. We added up the distances to get the total distance and added up the times to get the total time. Then we used the formula for average speed to get the answer.

Answer: Option A. -> Rs.0
To find out how much Monica spent on the fourth day, we can use the formula for calculating the average, which is:
Average = (Sum of values) / (Number of values)
We know that Monica's average expenses for 4 days is Rs. 6.0, so we can write:
6.0 = (Sum of expenses) / 4
Multiplying both sides by 4, we get:
Sum of expenses = 24
We also know that Monica spent Rs. 7.70 on the first day, Rs. 6.30 on the second day, and Rs. 10 on the third day. So the total amount she spent on these three days is:
7.70 + 6.30 + 10 = 24.00
Subtracting this amount from the sum of expenses for all 4 days, we can find how much she spent on the fourth day:
24.00 - 24 = 0
Therefore, Monica spent Rs. 0 on the fourth day. The correct option is A, Rs. 0.
In conclusion, we used the formula for calculating the average to find out the sum of expenses for all 4 days. We then subtracted the sum of expenses for the first three days from the total to find out how much she spent on the fourth day. Since the result was zero, we can conclude that Monica did not spend any money on the fourth day.

Answer: Option D. -> none of these
To find the raised average age of the class after the students leave and new students are admitted, we need to calculate the total age of the students both before and after the changes and then find the average.
Let's start by finding the total age of the 35 students before the changes:

• Average age of 35 students = 15 years 4 months
• Total age of 35 students = 35 * (15 years + 4 months)
• Since the age is in years and months, we need to convert the months to years to make the calculation easier:

4 months = 4 / 12 years = 1/3 yearsTotal age of 35 students = 35 * (15 + 1/3) years= 35 * (15 + 1/3)= 35 * 15 + 35 * 1/3= 525 + 35 / 3= 525 + 11.67= 536.67 yearsNext, we need to calculate the total age of the three students who left the class:

• Age of the first student = 18 years 1 month = 18 + 1/12 years
• Age of the second student = 17 years 6 months = 17 + 6/12 years
• Age of the third student = 15 years 9 months = 15 + 9/12 years
• Total age of the three students = 18 + 1/12 + 17 + 6/12 + 15 + 9/12

= 50.75 yearsSo, the total age of the 35 students after the three students leave the class is:

• Total age before the changes = 536.67 years
• Total age after the changes = 536.67 - 50.75

= 485.92 yearsNext, we need to calculate the total age of the 8 newly admitted students:

• Average age of 8 students = 16 years 5 months
• Total age of 8 students = 8 * (16 + 5/12) years

= 8 * 16.42 years= 131.36 yearsFinally, we need to calculate the total age of the class after the new students are admitted:

• Total age of the class = Total age before changes + Total age of newly admitted students

= 485.92 + 131.36= 617.28 yearsAnd the number of students in the class after the changes is:

• Total number of students = 35 - 3 + 8

= 40 studentsTherefore, the raised average age of the class after the changes is:

• Raised average age = Total age of the class / Total number of students

= 617.28 / 40= 15.432 yearsAs we can see, the raised average age is not one of the options given, so the correct answer is D. None of these.

Answer: Option B. -> 32⁰C , 40⁰ C

Answer: Option B. -> 58.25
The average value of each article can be calculated as follows:
Total cost of all articles = (number of shirts * cost per shirt) + (number of pairs of shoes * cost per pair of shoes) + (number of pants * cost per pant)= (13 * 50) + (15 * 60) + (12 * 65)= 650 + 900 + 780= 2330
Total number of articles = number of shirts + number of pairs of shoes + number of pants= 13 + 15 + 12= 40
Average value of each article = Total cost of all articles / Total number of articles= 2330 / 40= 58.25
Therefore, the correct option is B, i.e., 58.25.
Some relevant definitions and formulas used in the solution are:

• Average or mean: It is the sum of a set of numbers divided by the total number of numbers in the set.
• Total cost: It is the sum of the individual costs of all items.
• Total number: It is the sum of the individual numbers of all items.

Mathematically, the formulas used in the solution are:

• Total cost = (number of items * cost per item)
• Average value = Total cost / Total number

Answer: Option C. -> 22, 18 , 20

Answer: Option B. -> 24 years
Let the average age of the board of 8 trustees be x.
Then, the sum of the ages of the 8 trustees would be 8x.
Three years ago, the sum of their ages would have been (8x - 8*3) = (8x - 24).
Let the age of the trustee who has been replaced be y, and the age of the new member be z.
We know that z < y, since the new member is younger than the trustee he has replaced.
After the replacement, the sum of the ages of the 8 trustees remains the same as it was 3 years ago. Therefore, we have:
(8x - y + z) = (8x - 24)
Simplifying this expression, we get:
z - y = -24
Since z < y, we can rewrite this as:
y - z = 24
This means that the difference in ages between the trustee who has been replaced and the new member is 24 years.
Therefore, the answer is option B, 24 years.