This is the second part (questions 11-20) of the solutions of the Grade 8 MTAP 2015 Elimination Questions. You can read the solutions for questions 1-10 **here**. If you found any errors in the solution, please comment in the box below.

11.) If and , what is ?

**Solution**

**Answer: -12**

12.) Simplify .

**Solution**

**Answer:**

13.) If and are positive constants, simplify .

**Solution**

Note that , and

Now

This is already correct, but if you want your answer in radical form, the previous expression can be converted to

**Answer:** or

14.) What is the quotient when is divided by ?

**Solution**

**Answer**: remainder .

15.) In Item 14, what is the remainder?

**Answer**:

16.) If , what is ?

**Solution**

**Answer**:

17.) If and , what is ?

**Solution**

and

Substituting the given values above,

.

**Answer**: 238

18.) If the length, width, and height of an open-top rectangular box are cm, cm, and cm, what is its surface area?

**Solution**

The formula for finding the surface area of a rectangular prism with length , width and height is . Since the box is open, we subtract lw, which is the top face. So, the surface area of the open box is .

Substituting, we have

**Answer**:

19.) A man walked km for 2.5 hrs, then jogged km for 3.5 hrs, and finally walked again km for 4 hrs. If his average speed for the entire exercise was 4 kph, what is x?

**Solution**

**Answer**: 3/5 or 0.6

20.) Simplify .

**Solution**

We can group the expressions as sum and difference of two cubes.

Now, this is in the form of the difference of two squares .

So,

**Answer**: