Bissoy.com
Doctors Medicines MCQs Q&A

The average of fifteen numbers is 48.4. The average of first four numbers is 44.5, and that of last eight numbers is 55. The 5th number is 3 less than the 6th number but 3 more than the 7th number. What is the average of 5th and 6th numbers?

The average of fifteen numbers is 48.4. The average of first four numbers is 44.5, and that of last eight numbers is 55. The 5th number is 3 less than the 6th number but 3 more than the 7th number. What is the average of 5th and 6th numbers? Correct Answer 37.5

Given:

Average of 15 numbers = 48.4

Average of first four numbers = 44.5 

Average of last eight numbers = 55

Formula used:

Average = Sum of all observations/Number of observations

Sum of all observations = Average × Number of observations

Calculation:

Let 5th number be x then, 6th number be (x + 3)

And 7th number be (x - 3)

Sum of 15 numbers = 48.4 × 15 = 726

Sum of first four numbers = 44.5 × 4 = 178

Sum of last eight numbers = 55 × 8 = 440

According to the question, we get,

726 = 178 + 440 + x + x + 3 + x - 3

⇒ 3x = 726 - 618 = 108

⇒ x = 36

5th number = x = 36

6th number = (x + 3) = 36 + 3 = 39

Average of 5th and 6th numbers = (36 + 39)/2 = 75/2 = 37.5

∴ The average of 5th and 6th numbers are 37.5.

Related Questions

The average of 12 number is 70. The average of the first four numbers is 60 while the average of the last five number is \(33\frac{1}{3}\%\) more than the average of the first four numbers. The 6th number is 20 more than the 5th number while the 7th number is 10 more than the 6th number. By what percent is the 6th number more than the 5th number?
The average of ten numbers is 32.5. The average of first four numbers is 25.6 and that of the last three numbers is 38.2. The 5th number is 50% more than the 6th number and 8 less than the 7th number. What is the average of 5th and 7th numbers?
The average of twelve numbers is 46. The average of the first four numbers is 43 and that of the last five numbers is 49.4. The 5th and the 6th numbers are respectively 4 and 6 more than the 7th number. What is the average of the 5th and 7th numbers?
The average of the eight numbers is 32. The first two numbers average 28.5 and the next three numbers average 30. The 6th number is 50% more than the 8th number but 5 less than the 7th number. What is the average of the 6th and 8th numbers?
A,B,C,D,E,G and I are seven friends who study in three different standards namely 5th, 6th and 7th such that not less than two friends study in the same standard. Each friend also has a different favorite subject namely History, Civics, English, Bangla, Science , Maths , and Economics but not necessarily in the same order. A likes Maths and studies in the 5th standard with only one other friend who likes Bangla. I studies with tow other friends . Both the friends who study with I like languages (Here languages include only Science , English and Bangla ) . D studies in the 6th standard with only one person and does not like Civics . E studies with only one friend . The one who likes history does not study in 5th or 6th standard . E does not like languages. C does not like English , Science or Civics. Which combination represents E's favorite subject and the standard in which he studies?
Average of 13 numbers is 78. Average of the first five numbers is 88 and the average of the last five number is 37.5% less than the average of the first five numbers. 6th and 7th number are in the ratio 9 ∶ 11, while 7th and 8th number are in the ratio 10 ∶ 9. What is the largest number among three numbers?
The average of eight batsmen J, K, L, M, N, O, R, and T is compared. The number of batsman having average less than L are same as the number of batsman having average more than M. Average of T is less than M and more than K. Average of L is less than K. Average of two batsman lies between the average of M and L. Average of O is less than N and K both. Which of the following can be the correct sequence of their averages?
The average of fifteen numbers is 60. The average of the first seven numbers is 63 and the average of next five numbers is 59. The last number is half of the 13th number and the 14th number is four more than the last number. Which of the following is/are correct? I. Average of the last three numbers is an integer II. Fourteenth number is divisible by 11 III. Average of 13th and 15th number is not 65
There are eight cars A, B, C, D, E, F, G and H. Each car has a different price. Price of C is more than that of A and D. Price of at least two cars is less than A. Price of F is more than that of G and H. Price of D is less than G, but more than E. Price of B is less than H, but more than G. Price of at least four cars is more than that of C. Which of the following sequence is correct?
From the given table, what is the percentage of students scoring 40 or more, but less than 70. Scores Less than 20 Less than 30 Less than 40 Less than 50 Less than 60 Less than 70 Less than 80 No. of Students 12 19 22 31 38 46 50