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The mean of 2 numbers is 10.
One number is 10.
Find the other number.
Mean=10+x/2=10
= 10+x=20⇒
x=10
WHAT IS MEAN
the sum of the values in a set divided by the number of values in the set
The average of 4 numbers is 5.
If one number is 5, what is the average of the remaining 3 numbers?
Mean of 4 numbers = 5
One number = 5
Total sum=4×5=20
Sum of remaining 3 numbers = 20 – 5 = 15
Mean of remaining 3=15÷3=5
he mean of 10 numbers is 6.
If each number is increased by 2, find the new mean.
Mean of 10 numbers = 6
Each number increased by 2
New mean=6+2=8
✅ New mean = 8
WHAT IS RANGE ?HOW TO FIND RANGE?
the difference between the highest and lowest values. For example, if the given data set is {2,5,8,10,3}, then the range will be 10 – 2 = 8. Thus, the range could also be defined as the difference between the highest observation and lowest observatION
WHAT IS MODE ? HOW TO FIND MODE?
t
FREQUENTLY APPEARD NUMBER IS CALLED MODDE
The lowest temperature this week was -2°C and the highest was 7°C.
What is the range?
7−(−2)=7+2=9
Answer: 9°C
-3, 0, 5, -1, 7, -2, 4
FIND RANGE
10
-2.5, 3/4, -1, 0.75, 2.5, -3/2
FIND THE RANGE AND MODE
RANGE =5
MODE=0.75
-8, -3, 0, 2, -1, 5
FIND THE RANGE
13
A seesaw is measured at different positions along a playground (in meters):
-5 m, -2.5 m, 0 m, 2.5 m, 5 m, 0 m, -2.5 m
Questions:
What is the range of positions?
Which positions are most rEPEATED
RANGE=10
MODE=2,5 AND 0
A lab thermometer recorded these temperatures (in °C):
-1.1°C, -1.10°C, -1.0°C, -0.9°C, -1.0°C, -1.1°C, -0.95°C
Questions:
What is the range of temperatures?
Which temperature is the mode?
RANGE 0,2
MODE=-1.1
The mean of 7 numbers is 14. One number is mistakenly recorded as 20 instead of 10.
Find the correct mean.
By how much did the mean change due to the mistake?
Mean of 7 numbers = 14 → Total sum = 7×14=987 \times 14 = 987×14=98
One number recorded as 20 instead of 10
Step 1: Correct total sum:
Correct sum=98−20+10=88
Step 2: Correct mean:
Correct mean=88÷7≈12.57
Step 3: Change in mean:
Change=14−12.57≈1.43
The average daily income of a family for 5 days was ₹250.
On one day, the income was wrongly recorded as ₹300 instead of ₹200.
Wrong total:
250×5
=1250
Correct total:
1250−300+200
=1150
Correct mean:
1150\5
=₹230
fitness app shows that the average screen time of a student over 7 days is 3 hours per day.
Later, it was found that on one day the screen time was entered as 2 hours instead of 5 hours.
Find the correct average screen time.
Given average =3 hours for 7 days
Step 1: Wrong total screen time
3×7=21 hours
Step 2: Correct the error
Wrong entry = 2 hours
Correct entry = 5 hours
Correct total:
21−2+5
=24 hours
Step 3: Correct average
24\7=3.43
The mean of 5 numbers is 12. If we double each number and then add 3 to each, find the new mean.
Mean of 5 numbers = 12
Step 1: Total sum of numbers:
Sum=5×12=60\text{Sum} = 5 \times 12 = 60Sum=5×12=60
Step 2: Transform numbers: double each number and add 3
Doubling → sum becomes 2×60=120
Adding 3 to each → 5 numbers, so total added = 5×3=15
Step 3: New total sum = 120+15=135
Step 4: New mean = 135÷5=27
A teacher takes marks from two groups of students:
Group A: 10 students, mean = 40
Group B: 15 students, mean = 60
Later, it is discovered that one student in Group B had his marks recorded as 80 instead of 50.
Find the correct mean of Group B.
Find the combined mean of all students after correction.
Original total of Group B:
15×60=900
Correct total after fixing the error:
900−80+50=870
Correct mean of Group B:
870/15=58
✅ Correct mean of Group B = 58
Step 2: Combined mean of all students
Total students = 10 + 15 = 25
Total sum
Group A total+Group B total=(10×40)+870=400+870=1270
Combined mean:
1270/25=50.8
✅ Combined mean = 50.8
The average daily amount spent using a digital wallet by a person for 10 days is ₹450.
If on one day the person spent ₹950, answer the following:
Find the total amount spent in 10 days
1.450×10=₹4500
The mean of the first n natural numbers is 20.
Find the value of n and justify your steps.
n+1\2
=2n
=n+1 = 40
n=39
he average daily sales (in ₹) of a shop for 10 days is 500. On the 11th day, an unusually high sale of ₹2000 occurs.
Find the new mean for 11 days.
Suggest a better measure of central tendency to represent the daily sales without being affected by the extreme value, and justify your choice
tep 1: Total sales for 10 days
10×500=5000
Step 2: New total for 11 days
5000+2000=7000
Step 3: New mean
7000/11≈636.36
✅ New mean ≈ ₹636.36