Question

I need help finding out how long it took to type the essay

Answer 1

B. 2 4/7 hr

Explanation:

We have the following:

Rate Wiilie = 200 words in 6 hours

Rate Myra = 200 words in 4 1/2 hours

Together then it would be 200 words in x hours.

We can formulate the following equation:

`(200)/(x)=(200)/(6)+(200)/(4(1)/(2))`

We solve for x:

`\begin{gathered} (1)/(x)=(1)/(6)+(1)/(4(1)/(2)) \\ \\ (1)/(x)=(1)/(6)+(1)/((9)/(2)) \\ \\ (1)/(x)=(1)/(6)+(2)/(9) \\ \\ (1)/(x)=(1*9+2*6)/(6*9)=(9+12)/(54)=(21)/(54)=(7)/(18) \\ \\ x=(18)/(7)=2(4)/(7)\text{ hours} \end{gathered}`

So the correct answer is B. 2 4/7 hr