Question

Key is the youngest of 5 siblings. Starting with the oldest sibling, each sibling was born 2 years apart. Together, the siblings are 70 years old.

Which equation can be used to determine the age, a, of Key?

(1 point)
Responses

5a−20=70
5 A minus 20 is equal to 70

5a+20=70
5 A plus 20 is equal to 70

5a+70=20
5 A plus 70 is equal to 20

20a+5=70

Answer 1

Let's denote the age of Key as \( a \).

If Key is the youngest sibling, then the ages of the other siblings can be represented as follows:

- Oldest sibling: \( a + 8 \) (because each sibling is 2 years apart, and there are 4 older siblings)
- Second oldest: \( a + 6 \)
- Middle sibling: \( a + 4 \)
- Second youngest: \( a + 2 \)

Now, we can add the ages of all the siblings together:

\[
(a) + (a + 2) + (a + 4) + (a + 6) + (a + 8)
\]

This simplifies to:

\[
5a + 20
\]

According to the problem, the sum of their ages is 70. Therefore, we can set up the equation:

\[
5a + 20 = 70
\]

So, the equation that can be used to determine the age of Key is:

\[
5a + 20 = 70
\]

Thus, the correct response is:

**5a + 20 = 70**