# Tutor profile: Hufsa L.

## Questions

### Subject: Basic Chemistry

How can you tell the difference between an acid and a base?

An acid is a substance with a pH level < 7 and turns litmus paper red. A base has a pH level of > 7 and turns litmus paper blue.

### Subject: Calculus

What is the inverse for the equation : f(x) = 6x + 15

Step 1. Rewrite the equation using y and x: y = 6x + 15 Step 2. Switch the x and y. x = 6y + 15 Step 3. Solve for y. Start by subtracting both sides by 15 x - 15 = 6y Step 4. Divide both sides by 6. y = (x-15)/6 Step 5. Simplify. y = (1/6)(x-15)

### Subject: Algebra

Joshua walks into the store with $15.00 and wants to buy some toy cars and candy with his birthday money. Every toy car sells for $2.25 and every piece of candy sells for $1.00. If there are only 5 pieces of candy left in the store, how many cars, at most, can Joshua buy with his money if he also buys all the candy?

Joshua has $15.00 to begin with. Let x represent the number of cars and y represent the pieces of candy. The initial equation could be represented as 2.25x+ 1.00y = 15.00 The question also states that there are only five pieces of candy left and Joshua wants all of them so we can substitute 5 for y in the equation. 2.25x + 1.00(5) = 15.00 Now simplify 2.25x + 5 = 15.00 Subtract 5 from both sides. 2.25x = 10.00 Divide both sides by 2.25 to get the maximum number of toy cars that Joshua can buy if he also buys all of the remaining candy in the store. x = 4.44, meaning that Joshua can only get 4 toy cars maximum.