Average
- The average of 25 observations is 13. It was later found that an observation 73 was wrongly entered as 48. The new average is
-
View Hint View Answer Discuss in Forum
On the basis of given details in question , we have
Difference of two observations = 73 – 48 = 25
∴ New average = 13 + 25 = 14 25
Second method to solve this question with the help of given formula :
Here, n = 25, m = 13 , a = 73, b = 48Correct Average = m + (a - b) n
Correct Option: B
On the basis of given details in question , we have
Difference of two observations = 73 – 48 = 25
∴ New average = 13 + 25 = 14 25
Second method to solve this question with the help of given formula :
Here, n = 25, m = 13 , a = 73, b = 48Correct Average = m + (a - b) n Correct Average = 13 + (73 - 48) 25
Correct Average = 13 + 1 = 14
- The average weight of a group of 20 boys was calculated to be 89.4 kg and it was later discovered that one weight was misread as 78 kg. instead of 87kg. The correct average weight is
-
View Hint View Answer Discuss in Forum
According to question ,
Difference in weight = 87 – 78 = 9 kg∴ Correct average weight = 89.4 + 9 20
Correct average weight = 89.4 + 0.45 = 89.85 kg
Second method to solve this question with the help of given formula :
Here, n = 20, m = 89.4 a = 87, b = 78Correct Average = m + (a -b) n
Correct Option: D
According to question ,
Difference in weight = 87 – 78 = 9 kg∴ Correct average weight = 89.4 + 9 20
Correct average weight = 89.4 + 0.45 = 89.85 kg
Second method to solve this question with the help of given formula :
Here, n = 20, m = 89.4 a = 87, b = 78Correct Average = m + (a -b) n Correct Average = 89.4 + (87 - 78) 20 Correct Average = 89.4 + 9 20
Correct Average = 89.4 + 0.45 = 89.85 kg
- The average weight of 15 students in a class increases by 1.5kg when one of the students weighing 40 kg is replaced by a new student. What is the weight (in kg) of the new student ?
-
View Hint View Answer Discuss in Forum
According to question ,
Weight of the new student = (40 + 15 × 1.5) kg
Weight of the new student = (40 + 22.5) kg = 62.5 kg
Second method to solve this question with the help of given formula :
Here, N = 15, T = 40, t = 1.5
Weight of new Person = T + NtCorrect Option: D
According to question ,
Weight of the new student = (40 + 15 × 1.5) kg
Weight of the new student = (40 + 22.5) kg = 62.5 kg
Second method to solve this question with the help of given formula :
Here, N = 15, T = 40, t = 1.5
Weight of new Person = T + Nt
Weight of new Person = 40 + 15 × 1.5
Weight of new Person = 40 + 22.5 = 62.5 kg.
- The average weight of three men A, B and C is 84 kg. D joins them and the average weight of the four becomes 80 kg. If E whose weight is 3 kg more than that of D, replaces A, the average weight of B, C, D and E becomes 79 kg. The weight of A is
-
View Hint View Answer Discuss in Forum
The average weight of three men A, B and C = 84 kg
⇒ Total weight of A, B and C = 84 × 3 = 252 kg.
Again, the average weight of the four men = 80 kg
⇒ A + B + C + D = 80 × 4 = 320 kg.
∴ D = ( A + B + C + D ) - ( A + B + C ) = (320 – 252) kg. = 68 kg.
E = 68 + 3 = 71 kg.
B + C + D + E = 79 × 4 = 316 kg.Correct Option: C
The average weight of three men A, B and C = 84 kg
⇒ Total weight of A, B and C = 84 × 3 = 252 kg.
Again, the average weight of the four men = 80 kg
⇒ A + B + C + D = 80 × 4 = 320 kg.
∴ D = ( A + B + C + D ) - ( A + B + C ) = (320 – 252) kg. = 68 kg.
E = 68 + 3 = 71 kg.
B + C + D + E = 79 × 4 = 316 kg.
Now, (A + B + C + D) – (B + C + D +E) = (320 – 316) kg.
∴ A – E = 4 kg.
⇒ A = 4 + E = 4 + 71 = 75 kg
