NCDAP College-Level Math 5

Question 1

If a matrix A is 3×2 and matrix B is 2×4, what are the dimensions of AB?

Accepted Answer

3×4

Answer

The product of a 3×2 and a 2×4 matrix is a 3×4 matrix.

Question 2

What is the sum of the infinite geometric series 8 + 4 + 2 + 1 + …?

Accepted Answer

16

Answer

S = a/(1 − r) = 8/(1 − 0.5) = 16.

Question 3

Solve the system: x + y = 6, 2x − y = 3. What is x?

Accepted Answer

3

Answer

Adding the equations: 3x = 9, so x = 3.

Question 4

What is the 10th term of the arithmetic sequence 5, 8, 11, 14, …?

Accepted Answer

32

Answer

aₙ = 5 + (10 − 1)·3 = 5 + 27 = 32.

Question 5

Which value of x satisfies e^(2x) = 7?

Accepted Answer

(ln 7)/2

Answer

Take ln of both sides: 2x = ln 7, so x = (ln 7)/2.

(NCDAP) North Carolina Diagnostic Placement Test Practice Test