# Tutor profile: Riya A.

## Questions

### Subject: Trigonometry

cos(24°) + cos(5°) + cos(175°) + cos(204°) + cos(300°) = ?

=> cos(175°) = cos(180 - 5) = -cos(5) => cos(204°) = cos(180+24) = -cos(24) => cos(300°) = cos(360-60) = cos(60) So, result would be cos(60) that is 1/2

### Subject: Basic Math

A Laptop store gives a 10% discount to all students off the original cost of a Laptop. During a back to school sale an additional 15% is taken off the discounted price. James, a student at the local high school, purchases a laptop for $306. How much did it originally cost?

The equation, x - 0.10x - 0.15 (x - 0.10x) = 306, may be used to solve the problem. Solving for x gives 0.90x – 0.15x + 0.015x = 306, where x = 400. Thus, the original price was $400.

### Subject: Statistics

A test is administered annually. The test has a mean score of 300 and a standard deviation of 40. If Ravi’s z-score is 4.50, what was his score on the test?

X= μ+Zσ where μ is the mean, σ is the standard deviation and X is the score we’re calculating. Therefore, X = 300 + 40 * 4.5 = 480

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