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)

Answer 1

Let's define the ages of the siblings. If Key is the youngest sibling, we can denote the ages of the siblings as follows:

- The age of the oldest sibling: \( a + 8 \) (since there are 4 siblings older than Key and each is 2 years older than the one before)
- The age of the second oldest sibling: \( a + 6 \)
- The age of the third oldest sibling: \( a + 4 \)
- The age of the fourth oldest sibling: \( a + 2 \)
- The age of Key (the youngest sibling): \( a \)

Now, we can set up an equation based on the total combined age of the siblings, which is given as 70 years:

\[
(a + 8) + (a + 6) + (a + 4) + (a + 2) + a = 70
\]

Now, simplify the left side:

\[
5a + (8 + 6 + 4 + 2) = 70
\]
\[
5a + 20 = 70
\]

So, the equation that can be used to determine the age \( a \) of Key is:

\[
5a + 20 = 70
\]