High School

A number, [tex]n[/tex], is added to 15 less than 3 times itself. The result is 101. Which equation can be used to find the value of [tex]n[/tex]?

A. [tex]3n - 15 + n = 101[/tex]
B. [tex]3n + 15 + n = 101[/tex]
C. [tex]3n - 15 - n = 101[/tex]
D. [tex]3n + 15 - n = 101[/tex]

Answer :

Let's go through the problem step by step.

1. The phrase “15 less than 3 times itself” means we first multiply the number [tex]$n$[/tex] by 3 and then subtract 15. This gives us the expression:
[tex]$$
3n - 15.
$$[/tex]

2. The number [tex]$n$[/tex] is added to this expression, so we have:
[tex]$$
n + (3n - 15).
$$[/tex]

3. According to the problem, the result is equal to 101. Therefore, the equation becomes:
[tex]$$
n + (3n - 15) = 101.
$$[/tex]

4. Simplify the left-hand side by combining like terms:
[tex]$$
n + 3n - 15 = 4n - 15.
$$[/tex]

5. The simplified equation is:
[tex]$$
4n - 15 = 101.
$$[/tex]

Thus, the equation that can be used to find the value of [tex]$n$[/tex] is:
[tex]$$
3n - 15 + n = 101.
$$[/tex]

6. Solving the equation:
- Add the [tex]$n$[/tex] terms: [tex]$4n - 15 = 101$[/tex].
- Add 15 to both sides:
[tex]$$
4n = 101 + 15 = 116.
$$[/tex]
- Divide by 4:
[tex]$$
n = \frac{116}{4} = 29.
$$[/tex]

Therefore, the correct multiple-choice option is:

[tex]$$
\boxed{3n - 15 + n = 101.}
$$[/tex]