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find 5 consecutive odd numbers where the sum of the first three numbers is 15 greater than the sum of two numbers

User Tommy Lee
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1 Answer

4 votes

Answer:

The five odd numbers are:

23, 25, 27, 29, and 31

Explanation:

A random odd number is written as:

2*n + 1

Where n is an integer.

Then 5 consecutive odd numbers will be:

2*n + 1

2*(n + 1) + 1

2*(n + 2) + 1

2*(n + 3) + 1

2*(n + 4) + 1

Now we want that the sum of the first 3 numbers to be 15 greater than the sum of the two last numbers, then:

(2*n + 1) + (2*(n + 1) + 1) + (2*(n + 2) + 1) = 15 + (2*(n + 3) + 1) + (2*(n + 4) + 1)

Now we just need to solve this for n:

(2*n + 1) + (2*n + 3) + (2*n + 5) = 15 + (2*n + 7) + (2*n + 9)

6*n + 9 = (15 + 7 + 9) + 4*n

6*n - 4*n = 15 + 7 + 9 - 9

2*n = 15 + 7 = 22

n = 22/2 = 11

Then the five numbers are:

(2*11 + 1) = 23

(2*(11 + 1) + 1) = 25

(2*(11 + 2) + 1) = 27

(2*(11 + 3) + 1) = 29

(2*(11 + 4) + 1) = 31

User Woworks
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