The formula for the size of a file that was downloaded over time $t$ and at an average rate $r$ is $r \cdot t$ . Siena downloaded a file at a rate of $800 \text{ kilobytes per second}$ for about $110 \text{ seconds}$ . What calculation will give us the estimated size of the file Siena downloaded, in megabytes? Choose $1$ answer: $\newline$ (A) $800 \cdot 110 \cdot 60$ $\newline$ (B) $800 \cdot \frac{110}{60}$ $\newline$ (C) $800 \cdot 1000 \cdot 110$ $\newline$ (D) $\frac{800}{1000} \cdot 110$

Full solution

Q. The formula for the size of a file that was downloaded over time

t

and at an average rate

r

r \cdot t

. Siena downloaded a file at a rate of

800 \text{ kilobytes per second}

for about

110 \text{ seconds}

. What calculation will give us the estimated size of the file Siena downloaded, in megabytes? Choose

1

answer:

\newline

(A)

800 \cdot 110 \cdot 60

\newline

(B)

800 \cdot \frac{110}{60}

\newline

(C)

800 \cdot 1000 \cdot 110

\newline

(D)

\frac{800}{1000} \cdot 110

Identify Formula: Identify the formula to use for the calculation. $\newline$ The formula given is $r*t$ , where $r$ is the rate of download and $t$ is the time taken to download the file.
Plug in Values: Plug in the values for $r$ and $t$ into the formula. $\newline$ Siena downloaded a file at a rate of $800$ kilobytes per second for about $110$ seconds. $\newline$ So, $r = 800$ kilobytes/second and $t = 110$ seconds.
Calculate Size: Calculate the size of the file in kilobytes. $\newline$ Using the formula $r*t$ , we get $800$ kilobytes/second $*$ $110$ seconds $=$ $88000$ kilobytes.
Convert to Megabytes: Convert the file size from kilobytes to megabytes. $\newline$ There are $1000$ kilobytes in a megabyte. Therefore, to convert kilobytes to megabytes, we divide by $1000$ . $\newline$ $88000$ kilobytes $\div 1000 = 88$ megabytes.
Match with Choices: Match the calculation with the given choices. $\newline$ The correct calculation is $(800 \text{ kilobytes/second}) \times 110 \text{ seconds} / 1000 = 88 \text{ megabytes}$ . $\newline$ This matches with choice (B) $800\times(110)/(60)$ , if we recognize that the division by $60$ is incorrect and should be division by $1000$ to convert kilobytes to megabytes. Therefore, none of the given choices are correct.