# the average of 5 numbers is 7. the average of top 2 number is 3 and average of last two number is 6 . what is the third number

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## If the average of five numbers is 10 , and the fifth number is 6 , find the average of the first four numbers.

Click here👆to get an answer to your question ✍️ If the average of five numbers is 10 , and the fifth number is 6 , find the average of the first four numbers.

Question

## If the average of five numbers is 10, and the fifth number is 6, find the average of the first four numbers.

**A**

## 9

**B**

## 10

**C**

## 11

**D**

## 12

**E**

## 13

Easy

## [Solved] The average of 3 numbers is 7 and the average of first two n

Given: The average of 3 numbers = 7 The average of the first 2 numbers = 4 Formula used: Average = (Sum of values/number of values) Calculation: The avera

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## The average of 3 numbers is 7 and the average of first two numbers is 4. What is the third number?

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## Detailed Solution

Download Solution PDF

**Given:**

The average of 3 numbers = 7

The average of the first 2 numbers = 4

**Formula used:**

Average = (Sum of values/number of values)

**Calculation:**

The average of 3 numbers = 7

Sum of 3 numbers ⇒ 7 × 3 ⇒ 21

The average of 2 numbers = 4

Sum of 2 numbers ⇒ 4 × 2 ⇒ 8

Third Number = 21 – 8 = 13

**∴ The third number is 13.**

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## The average of 5 numbers is 9 and the average of the last three numbers is 5. What is the average of the first two numbers?

Answer (1 of 12): \frac{x_{1}+x_{2}+x_{3}+x_{4}+x_{5}}{5} = 9\\ \frac{x_{3}+x_{4}+x_{5}}{3} = 5\\ x_{3}+x_{4}+x_{5} = 15\\ x_{1}+x_{2}+x_{3}+x_{4}+x_{5} = 45\\ x_{1}+x_{2} = 45-(x_{3}+x_{4}+x_{5})\\ x_{1}+x_{2} = 45-15 = 30\\ \text{ Average } = \frac{\text{Sum of numbers}}{\text{ No of numb...

The average of 5 numbers is 9 and the average of the last three numbers is 5. What is the average of the first two numbers?

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Sort Niranjan Krishna

Loves Mathematics and Physics.Author has 143 answers and 80.8K answer views2y

x 1 + x 2 + x 3 + x 4 + x 5 5 =9 x1+x2+x3+x4+x55=9 x 3 + x 4 + x 5 3 =5 x3+x4+x53=5 x 3 + x 4 + x 5 =15 x3+x4+x5=15 x 1 + x 2 + x 3 + x 4 + x 5 =45 x1+x2+x3+x4+x5=45 x 1 + x 2 =45−( x 3 + x 4 + x 5 ) x1+x2=45−(x3+x4+x5) x 1 + x 2 =45−15=30 x1+x2=45−15=30 Average = Sum of numbers No of numbers

Average =Sum of numbers No of numbers

∴ Average = x 1 + x 2 2 ∴ Average =x1+x22 = 30 2 =302 =15 =15 Related questions

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The average of 9 numbers is 18. The average of the first 5 numbers is 22 and that of the last 3 numbers is 15. What are the 6th numbers?

Sumanta Kumar Nandi

Senior Section Engineer at Ministry of Railways, India (1988–present)2y

Total of 5 numbers is 5×9=45

Total of last 3 numbers is 5×3=15

Total of remaining 2 numbers is 45–15=30

Average of 2 numbers is 30÷2=15

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Nandan Singh

Private Tutor (2001–present)Author has 619 answers and 668.2K answer views2y

Sum of all five numbers =5*9=45

Sum of the last 3 numbers =3*5=15

Sum of the first 2 numbers =45–15=30

Average of the first two numbers. =30/2=15.

Ankaleshwar Shiv

Algebra, Geometry and TrigonometryAuthor has 94 answers and 163.7K answer views3y

Related

The average of three numbers is 29. The average of two of these numbers is 38. What is the third number?

Let the three numbers be x, y and z.

As per question: (x+y+z)/3 = 29

so, x+y+z = 29*3 = 87

Also,

average of any two numbers i.e., (x+y)/2 = 38

so, x+y = 38*2 = 76

Hence, The third number z = 87 - 76 = 11

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What is the average of 5 and what number is 9?

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The average of 5 numbers is 14. The average of three of the numbers is 12. What is the average of the other two numbers?

The average (mean) of three numbers is 10. The first two numbers are 10 and 4. What is the third number?

The average of 25 numbers is 48.2. If the average of the first 10 numbers is 47 and the average of the last 12 numbers is 49, what is the average of 58, 69 and the remaining numbers?

Udit Gautam

Former Member at The Placement Cell, PGDAV College (2022–2022)2y

Let the five nos. be a, b, c, d and e.

Given, (a+b+c+d+e)/5=9 So, =>a+b+c+d+e=5×9=45 Also given, (c+d+e)/3=5 So, =>c+d+e=5×3=15 So, =>a+b+15=45 =>a+b=45–15=30 Now, =(a+b)/2 =30/2 =15

Hence, the average of first two numbers is 15

Hope it helps Thank you Roland Neville

Former Retired Teacher, Formerly in Engineering.Author has 797 answers and 180.7K answer views2y

Related

The average of five numbers is six. Out of these five numbers, the average of three numbers is four. What will the average be of the other two numbers?

Average of all five is 6 → total is 30

Average of three is 4 → Total of the three is 12

→ Total of the last two is 18

→ Average of the last two is 9

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Krishna Singh

Bachelor of Science in Statistics (academic discipline) & Mathematician And Theoretical Physicist, Patna Science College, Patna (Graduated 2020)Author has 451 answers and 1.5M answer views3y

Guys, does anyone know the answer?