Answer:
20
Step-by-step explanation:
one way is guess and check method, you draw a table and try out 3 different consecutive even numbers to see which 3 add up to 66
a
7
because 4a + 7 - 7
35 - 7
equals 4a
28
and 4a/4
28/4
equals a
7
Answer:

General Formulas and Concepts:
Order of Operations: BPEMDAS
Midpoint Formula: 
Step-by-step explanation:
<u>Step 1: Define points</u>
J (4, 6)
K (0, -4)
<u>Step 2: Find midpoint</u>
- Substitute:

- Add/Subtract:

- Divide:

Answer:
There are 6 adults. <em>My mistake! I had the wrong equation. 3 + 9a = 57.</em>
Step-by-step explanation:
- <u>There is only 1 child in the group.</u>
- Cost for children is 3$.
- <u>The cost for adults is 9$.</u>
- 9 * 6 = 54
- 3 * 1 = 3
- 3 + 9a = 57
- Simplify:
- 6 Adults.