# Tutor profile: Cyril J.

## Questions

### Subject: Basic Math

What is 20 percent of $30.

The easiest way to tackle such a problem is by simply using the formula: "is/of=x/100 percent". We're looking for "is", but we have 20%. We are also given a total of $30. When we plug the numbers into the formula we have: x/30=20/100. When we cross multiply, we have 100 times x=20 times 30. This gives us 100x=600. Finally, we divide 100x/100 and 600/100. We will now get x=600/100=6. Let's put this into perspective. If I would like to buy a sweater that costs $30, but it's on sale for 20% off, the sweater would actually cost me 30-6= $24

### Subject: Biology

What do Enzymes and Antibodies have in common? What makes them unique?

Enzymes and Antibodies are both proteins that are found in all living things. Enzymes are proteins that the body makes to break down other proteins and larger molecules so that they are small enough to be taken up by the cell. Antibodies are components of the body that is made by the immune system to protect against foreign bodies. They keep us healthy and help our body fight against infections.

### Subject: Algebra

Solve: 2(a -3) + 4b - 2(a -b -3) + 5

In this example, the best way to tackle the question would include the order of operations, also known as PEMDAS. This stands for PEMDAS(Parenthesis, Exponents, Multiplication, Division, Addition, Subtraction). You start with 'P' in PEMDAS and work your way to 'E', 'M', 'D', 'A', and 'S' from left to right. In this example, we'll start with (a-3) since it's in parenthesis. There is nothing we can do with that because there are 2 different variables, so we'll move on to the next parenthesis, (a-b-3). There is nothing we can do with that either. Next we'll move on to Exponents. Since there are no Exponents, we'll skip that and move to Multiplication. We will start from left to right. We can multiply the 2 with (a-3), giving us 2a-2(3)= 2a-6. We can also multiply the -2 by (a-b-3), which will give us -2a+2b+6. The reason why we used -2 is because we have subtraction. Putting it all together, we have 2a-6+4b-2a+2b+6. Now we simply add up all the 'a', 'b', and numbers. 2a-2a=0. 6-6=0. 4b+2b=6b. Then, we will get 0+0+6b=6b.

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