A number in scientific notation has the format 0.000 x 10^exponent. To convert to scientific notation, move the decimal point to the right or the left until the number is a decimal between 1 and 10. The exponent of the 10 is the number of places you moved the decimal point and is positive if you moved the decimal point to the left and negative if you moved it to the right:

0.0004397 in scientific notation is 4.397 x 10^-4

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

\( \frac{15 + 7 + 13 + 9}{4} \) = \( \frac{44}{4} \) = 11

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

\( \frac{9}{100} \) x 10 = \( \frac{9 \times 10}{100} \) = \( \frac{90}{100} \) = 0.9 errors per hour

So, in an average hour, the machine will produce 10 - 0.9 = 9.1 error free parts.

The machine ran for 24 - 9 = 15 hours yesterday so you would expect that 15 x 9.1 = 136.5 error free parts were produced yesterday.

The distributive property for division helps in solving expressions like \({b + c \over a}\). It specifies that the result of dividing a fraction with multiple terms in the numerator and one term in the denominator can be obtained by dividing each term individually and then totaling the results: \({b + c \over a} = {b \over a} + {c \over a}\). For example, \({a^3 + 6a^2 \over a^2} = {a^3 \over a^2} + {6a^2 \over a^2} = a + 6\).

Average speed in miles per hour is the number of miles traveled divided by the number of hours: