The key to this problem is understanding this problem is understanding how odd (or even) numbers are related.
Lets look at the first few odd numbers: 1, 3, 5, 7, 9, .... What can you do to each odd number to get the next odd number? Think about it for a bit.
The answer is, add two. If you start with any odd number and add two, you get the next odd number. (The same is true of even numbers.)
As you wrote above, we can express an odd number as 2n+1, where n is any integer. For example, 7 is 2(3)+1, 15 is 2(7)+1, 185 is 2(92)+1, etc.
Lets look at what you're trying to solve now.
Let 2n+1 be the first odd number. What will the next one be? Add two:
Let 2n+3 be the next odd number. Again, what is the next one? Add two:
Let 2n+5 be the third odd number.
The sum of those three numbers must be 99. You don't have to have the parenthesis here, but I think they help clarify where everything comes from.
(2n+1) + (2n+3) + (2n+5) = 99
Add like terms, and solve for n:
6n + 9 = 99
6n = 90
n = 15
The three odd numbers we want are:
2(15)+1 = 31
2(15)+3 = 33
2(15)+5 = 35
Double check: 31+33+35 = 99?
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Your second problem you can do pretty much the same way. I'll get you started, and hopefully you can finish it up on your own.
Let 2n be the first even number. What will the next even number be? Add two:
Let 2n+2 be the second even number. What will the next two numbers be? I'll leave that up to you to figure out.
The sum of those four numbers is 148.
(2n) + (2n+2) + (...) + (...) = 148
Again, add like terms to solve for n, then plug n back into the formulas for your 4 numbers to find the final answer.
I hope this helps, please comment if you have further questions!
