Question

The sum of five consecutive numbers is 20. What is the sum of first three consecutive numbers ?
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Answer 1

Answer:

9

Step-by-step explanation:

Let the 5 consecutive numbers be x, x + 1, x +2, x + 3 and x + 4

x + x + 1 + x + 2 + x + 3 + x + 4 = 20

5x + 10 = 20

5x = 10

x = 2

Sum of first 3 numbers,

i.e. x + x + 1 + x + 2

= 2 + 2 + 1 + 2 + 2

= 2 + 3 + 4

= 9

Answer 2

Answer:

9

Step-by-step explanation:

Let the five consecutive numbers be = x, x + 1, x + 2, x + 3, x + 4

Therefore,

x + (x + 1) + (x + 2) + (x + 3) + (x + 4) = 20

5x + 10 = 20

5x = 20 - 10

5x = 10

x = 2

First three consecutive numbers = x, x + 1, x + 2

Sum of the first three consecutive numbers =

x + x + 1 + x + 2

3x + 3

substituting value of x in the above equation

3(2) + 3

6 + 3 = 9