Answer:
The student should charge $210 for typing the paper ⇒ answer C
Explanation:
* Lets explain how to solve the problem
- The rate of the student's typing is 50 words per minute
- The students charges twenty dollars per hour to type the college
papers
- There is a paper contains 31,500 words
- We want to now how much the student should charge for it
* At first lets find his rate per hour
∵ 1 hour = 60 minutes
∴ 1 minute = 1/60 hours
∵ His rate = 50 words / 1 minute
- Lets change the minute to hour
∴ His rate = 50/(1 × 1/60) = 3000 words per hour
* Lets find the time he needs to finish the paper
∵ The paper contains 31,500 words
∵ Time = The number of words ÷ his rate of typing
∵ his rate is 3000 words per hour
∴ Time = 31,500 ÷ 3000 = 10.5 hours
∴ He needs 10.5 hours to finish the paper
∵ He charges $20 per hour
∵ The time to finish the paper is 10.5 hours
∵ The price of typing the paper = the charge per hour × number
of hours
∴ The price of typing the paper = 20 × 10.5 = 210
∴ The student should charge $210 for typing the paper