To add these fractions, first find the lowest common multiple of their denominators. The first few multiples of 2 are [2, 4, 6, 8, 10, 12, 14, 16, 18, 20] and the first few multiples of 10 are [10, 20, 30, 40, 50, 60, 70, 80, 90]. The first few multiples they share are [10, 20, 30, 40, 50] making 10 the smallest multiple 2 and 10 share.

Next, convert the fractions so each denominator equals the lowest common multiple:

\( \frac{3 x 5}{2 x 5} \) + \( \frac{8 x 1}{10 x 1} \)

\( \frac{15}{10} \) + \( \frac{8}{10} \)

Now, because the fractions share a common denominator, you can add them:

\( \frac{15 + 8}{10} \) = \( \frac{23}{10} \) = 2\(\frac{3}{10}\)

Betty scored 92% on the test meaning she earned 92% of the possible points on the test. There were 300 possible points on the test so she earned 300 x 0.92 = 276 points. Each question is worth 3 points so she got \( \frac{276}{3} \) = 92 questions right.

The amount of flour you need is (2\(\frac{7}{8}\) - \(\frac{5}{8}\)) cups. Rewrite the quantities so they share a common denominator and subtract:

(\( \frac{23}{8} \) - \( \frac{5}{8} \)) cups
\( \frac{18}{8} \) cups
2\(\frac{1}{4}\) cups

To find the average of these 4 numbers add them together then divide by 4:

\( \frac{11 + 5 + 11 + 5}{4} \) = \( \frac{32}{4} \) = 8

First, solve for \( \left|c + 1\right| \):

\( \left|c + 1\right| \) + 7 = -8
\( \left|c + 1\right| \) = -8 - 7
\( \left|c + 1\right| \) = -15

The value inside the absolute value brackets can be either positive or negative so (c + 1) must equal - 15 or --15 for \( \left|c + 1\right| \) to equal -15:

So, c = 14 or c = -16.