Question

The number of words maria typed varied directly with the amount of time she spent typing. if she typed 165 words in 3 minutes, how long would it take her to type 495 words?

Answer 1

Dimensional analysis allows us to compute the answer:

`\frac{165\text{ words}}{3\text{ minutes}}=\frac{495\text{ words}}{n}`
Cross multiply

`n\cdot165\text{ words}=495\text{ words}\cdot3\text{ minutes}`
Divide

`n=3\cdot(495)/(165)\text{ minutes}=3\cdot3\text{ minutes}=9\text{ minutes}`
It would take her 9 minutes.