# Tutor profile: Corrine B.

## Questions

### Subject: Basic Math

An item is discounted at 5% off. The item is purchased for $76. What was the original cost of the item?

In order to calculate discounts you need to multiply the percentage (once converted to a decimal) by the original price, and then subtract that amount from the original price. In this case, since the original price is unknown, you label it as variable x. Therefore the equation to solve this would be: x - 0.05x = 76. This is because you are subtracting the discount (which is 5% of x or 0.05x) from the original price x to get the final discounted amount of $76. Rearranging this equation and solving for x shows that the original price is therefore $80. You can check the accuracy of this answer by calculating 5% of 80 (which is $4), and subtracting that from 80, which gives you the discounted price of $76 that was paid for in the question.

### Subject: Chemistry

What is an ionic bond?

An ionic bond is a type of chemical bond that occurs between two ions that are oppositely charged. In this type of bond, electrons that are on the outermost shell of an atom (called valence electrons), are completely transferred between the atoms that are bonding. In this process, one atom loses an electron (electron donor) and one atom gains an electron (electron acceptor).

### Subject: Biology

How does active cell transport work to move particles across the cell membrane?

Active transport involves the use of energy to move particles against the concentration gradient. This means that the particles are moving from areas of low concentration to areas of high concentration. The energy that is used to achieve this movement is ATP, which is created from cellular respiration in our body.