The first claim,
"If 2<em>n</em> + 4 is even, then <em>n</em> is even"
is false; as a counterexample, consider <em>n</em> = 1, which is odd, yet 2•1 + 4 = 6 is even.
The second claim,
"If <em>n</em> is even, then (<em>n</em> + 3)² is odd"
is true. This is because
(<em>n</em> + 3)² = <em>n</em> ² + 6<em>n</em> + 9
<em>n</em> ² + 6<em>n</em> is even because <em>n</em> is even. 9 is odd. The sum of an even and odd integer is odd.
10 of the math problems is 40%
40/4 = 10%
10/4 = 2.5 questions
10% = 2.5 questions
10% x 10 = 100%
2.5 questions x 10 = 25 questions
25 questions is the answer
