The hourly error rate for this machine is the error rate in parts per 100 multiplied by the number of parts produced per hour:

\( \frac{4}{100} \) x 7 = \( \frac{4 \times 7}{100} \) = \( \frac{28}{100} \) = 0.28 errors per hour

So, in an average hour, the machine will produce 7 - 0.28 = 6.72 error free parts.

The machine ran for 24 - 9 = 15 hours yesterday so you would expect that 15 x 6.72 = 100.8 error free parts were produced yesterday.

Use PEMDAS (Parentheses, Exponents, Multipy/Divide, Add/Subtract):

5 + (2 + 5) ÷ 2 x 3 - 3²
P: 5 + (7) ÷ 2 x 3 - 3²
E: 5 + 7 ÷ 2 x 3 - 9
MD: 5 + \( \frac{7}{2} \) x 3 - 9
MD: 5 + \( \frac{21}{2} \) - 9
AS: \( \frac{10}{2} \) + \( \frac{21}{2} \) - 9
AS: \( \frac{31}{2} \) - 9
AS: \( \frac{31 - 18}{2} \)
\( \frac{13}{2} \)
6\(\frac{1}{2}\)

To take the square root of a fraction, break the fraction into two separate roots then calculate the square root of the numerator and denominator separately:

\( \sqrt{\frac{49}{64}} \)
\( \frac{\sqrt{49}}{\sqrt{64}} \)
\( \frac{\sqrt{7^2}}{\sqrt{8^2}} \)
\(\frac{7}{8}\)

By buying two shirts, Damon will save $20 x \( \frac{40}{100} \) = \( \frac{$20 x 40}{100} \) = \( \frac{$800}{100} \) = $8.00 on the second shirt.

So, his total cost will be
$20.00 + ($20.00 - $8.00)
$20.00 + $12.00
$32.00

To divide terms with radicals, divide the coefficients and radicands separately:

\( \frac{42\sqrt{36}}{6\sqrt{9}} \)
\( \frac{42}{6} \) \( \sqrt{\frac{36}{9}} \)
7 \( \sqrt{4} \)