i need help and could you plz explain

Question

Beatrice started babysitting when she was in high school. She has built a reputation for herself and has become popular among the neighborhood parents. Beatrice charges $10/h and gets a $5 automatic tip. Beatrice needs $100 to buy a present for her mother. She wants to find out the minimum number of hours she needs to babysit at one job to get the money she needs. (a) Write an inequality and solve it to help Beatrice figure out the minimum number of hours. Identify what the variable is and what it represents. Show your work. Justify each step in the solution. (c) Beatrice doesn't charge for partial hours. What is the minimum number of hours that she needs to work at one job to make at least $100? Round your answer to the nearest hour. Justify your answer.

Answer 1

100 < 10h + 5

The inequality is 100 less than or equal to 10*h + 5 because Beatrice has to make at least $100. The variable h=hours. You can make the variable x=hours. Because she receives an automatic $5 tip, that is added to the 10h. It is not 15h because the tip is not hourly, it is added on top of the total money she earns hourly. 

Isolate the variable

100 < 10h +5

-5               -5    subtract 5 from both sides

95 < 10h    divide 10 from both sides to get h by itself

9.5 < h      Beatrice needs to work at least 9.5 hours to make $100 dollars

Because she does not charge for partial hours, she needs to work at least 10 hours to make $100. We round 9.5 up to 10. We cannot round down to 9 because she would only make $95 at 9 hours.

The answer is 10 hours