Enable contrast version

Tutor profile: Le Z.

Inactive
Le Z.
Experienced Tutor for High School and Undergraduate Math, Science, and Economics Courses
Tutor Satisfaction Guarantee

Questions

Subject: Chemistry

TutorMe
Question:

50 mL of 0.10 M NaOH is mixed with 150 mL of 0.20 M HCl. What is the pH of the resultant mixture?

Inactive
Le Z.
Answer:

We calculate the excess [H+]: [H+] = ((150 mL)(0.20 M) - (50 mL)(0.10 M))(50 mL + 150 mL) = 0.125 M pH = -log[H+] = 0.90

Subject: Economics

TutorMe
Question:

John has 2 options: a) A lottery has 30% of winning $40 and 70% of winning $80. b) The other option is to receive $60 with 100% certainty. John's personal utility function is u(x) = x^(1/2). Will he play the lottery?

Inactive
Le Z.
Answer:

John's expected utility if he plays the lottery is: E(u(x)) = (0.3)($40)^(1/2) + (0.7)($80)^(1/2) = 8.15 John's expected utility if takes the $60 is: E(u(x)) = (1.0)($60)^(1/2) = 7.75 Thus, he will play the lottery

Subject: Statistics

TutorMe
Question:

A manufacturer of lightbulbs has found that the lifetime hours of their lightbulbs is normally distributed with a mean of 1100 hours and standard deviation of 150 hours. 97.5% of all their manufactured lightbulbs will last at least how many hours?

Inactive
Le Z.
Answer:

You should realize that 97.5% indicates 2 standard deviations from the mean. And this would be 2 standard deviations BELOW the mean, because we are talking about the top 97.5% of the dataset. Thus, 1100 - 2(150) = 800 hours.

Contact tutor

Send a message explaining your
needs and Le will reply soon.
Contact Le

Request lesson

Ready now? Request a lesson.
Start Lesson

FAQs

What is a lesson?
A lesson is virtual lesson space on our platform where you and a tutor can communicate. You'll have the option to communicate using video/audio as well as text chat. You can also upload documents, edit papers in real time and use our cutting-edge virtual whiteboard.
How do I begin a lesson?
If the tutor is currently online, you can click the "Start Lesson" button above. If they are offline, you can always send them a message to schedule a lesson.
Who are TutorMe tutors?
Many of our tutors are current college students or recent graduates of top-tier universities like MIT, Harvard and USC. TutorMe has thousands of top-quality tutors available to work with you.