To determine the first number when the sum of two consecutive numbers is 157, we can use the given equation [tex]\(2n + 1 = 157\)[/tex]. Here, [tex]\(n\)[/tex] represents the first number.
Let's solve the equation step by step:
1. Start with the equation:
[tex]\[
2n + 1 = 157
\][/tex]
2. Isolate the term with [tex]\(n\)[/tex] by subtracting 1 from both sides of the equation:
[tex]\[
2n + 1 - 1 = 157 - 1
\][/tex]
This simplifies to:
[tex]\[
2n = 156
\][/tex]
3. Solve for [tex]\(n\)[/tex] by dividing both sides by 2:
[tex]\[
n = \frac{156}{2}
\][/tex]
[tex]\[
n = 78
\][/tex]
So, the first number is 78.
The correct answer is:
B. 78
