Average
- The average weight of 12 crewmen in a boat is increased by 1/3 kg, when one of the crewmen whose weight is 55 kg is replaced by a new man. What is the weight of that new man?
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Total increase in weight = 12 × 1 = 4 3
Weight of the new man = Weight of the crewmen + Total increase in weight
∴ Weight of the new man = 55 + 4 = 59 kg
Second method to solve this question with the help of given formula :Here, N = 12, T = 55, t = 1 3
Weight of new man = T + Nt
Correct Option: D
Total increase in weight = 12 × 1 = 4 3
Weight of the new man = Weight of the crewmen + Total increase in weight
∴ Weight of the new man = 55 + 4 = 59 kg
Second method to solve this question with the help of given formula :Here, N = 12, T = 55, t = 1 3
Weight of new man = T + NtWeight of the new man = 55 + 12 × 1 3
Weight of the new man = 55 + 4 = 59 kg.
- Average weight of 25 persons is increased by 1 kg when one man weighing 60 kg is replaced by a new person. Weight of new person is :
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According to question ,
Total weight increased = 1 × 25 = 25 kg
∴ Weight of new person = weight of man + Total weight increased
Weight of new person = 60 + 25 = 85 kg
Second method to solve this question with the help of given formula :
Here, N = 25, T = 60 , t = 1Correct Option: D
According to question ,
Total weight increased = 1 × 25 = 25 kg
∴ Weight of new person = weight of man + Total weight increased
Weight of new person = 60 + 25 = 85 kg
Second method to solve this question with the help of given formula :
Here, N = 25, T = 60 , t = 1
Weight of New person = T + Nt
Weight of New person = 60 + 25 × 1 = 85 Kg
- The average weight of 20 students in a class is increased by 0.75 kg when one of the students weighing 30 kg is replaced by a new student. Weight of the new student (in kg) is :
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Here , Increase in weight = 0.75 kg
According to question ,
Required answer = 30 + 20 × 0.75
Required answer = 30 kg + 15 kg = 45 kg
Second method to solve this question with the help of given formula :
Here, N = 20, T= 30, t = 0.75
Weight of New student = T + NtCorrect Option: C
Here , Increase in weight = 0.75 kg
According to question ,
Required answer = 30 + 20 × 0.75
Required answer = 30 kg + 15 kg = 45 kg
Second method to solve this question with the help of given formula :
Here, N = 20, T= 30, t = 0.75
Weight of New student = T + Nt
Weight of New student = 30 + 20 × 0.75
Weight of New student = 30 + 15 = 45 kg
- Of the three numbers, second is twice the first and also thrice the third. If the average of the three numbers is 44, the largest number is :
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Let third number be p.
∴ Second number = 3pand first number = 3 p 2 Now, p + 3p + 3p = 3 × 44 2 ⇒ 8p + 3p = 3 × 44 2
⇒ 11p = 6 × 44
Correct Option: B
Let third number be p.
∴ Second number = 3pand first number = 3 p 2 Now, p + 3p + 3p = 3 × 44 2 ⇒ 8p + 3p = 3 × 44 2
⇒ 11p = 6 × 44⇒ p = 6 × 44 = 24 11
The largest number = 3p = 3 × 24 = 72
- Of the three numbers, first is twice the second and second is twice the third. The average of three numbers is 21. The smallest of the three numbers is
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Let the third number be n.
∴ The second number = 2n
and the third number = 2 × 2n = 4nAccording to the question, 4n + 2n + n = 21 3
⇒ 7n = 21 × 3⇒ n = 21 × 3 = 9 7
Second method to solve this question :
a = 2, b = 2, y = 21First number = 3ab y 1 + b + ab First number = 3 × 2 × 2 × 21 1 + 2 + 4
Correct Option: A
Let the third number be n.
∴ The second number = 2n
and the third number = 2 × 2n = 4nAccording to the question, 4n + 2n + n = 21 3
⇒ 7n = 21 × 3⇒ n = 21 × 3 = 9 7
Second method to solve this question :
a = 2, b = 2, y = 21First number = 3ab y 1 + b + ab First number = 3 × 2 × 2 × 21 1 + 2 + 4 First number = 12 × 21 = 36 7 Second number = 3b y 1 + a + ab Second number = 3 × 2 × 21 = 18 7 Third number = 3 y 1 + a + ab Third number = 3 × 21 = 9 7
