Question

The sum of 3 consecutive odd numbers is 51
What is the second number in this sequence?

Answer 1

second number= 17

Explanation:

first number=a

second number=b

third number = c

we have:

a+b+c=51 equation 1

a=2n+1 equation 2

b=2n+3 equation 3

c=2n+5 equation 4

using equations 2, 3 and 4 in equation 1, we have

2n+1+2n+3+2n+5=51

6n+9=51

6n=51-9

6n=42

n=42/6

n=7

so we have

a=(2*7)+1 =15 first number

b=(2*7)+3 =17 second number

c= (2*7)+5 =19 third number