Answer:
a = 12 years
Step-by-step explanation:
Mark is 6 years older than his brother Sam. Now, we are asked to represent Sam’s age by a. This means that if Sam is a years old, Mark is (a + 6) years old.
The sum of their ages is 30, this means that when we add their ages together, we get the sum of thirty.
Mathematically this means a + a + 6 = 30
2a + 6 = 30
This is the equation needed to get a. To get a , we proceed to solve the equation to completion.
2a = 30 - 6
2a = 24
a = 24/2
a = 12
The answer is the first answer is the first option.

С = 2πr [π≈3.14]
220 = 2 * 3.14 * r
220 = 6.28r
r = 220/6.28 ≈ 35 cm ← <span>to the nearest whole number.</span>
It’s is 6 because I added it all up and all you have to do is division