Math Answers

D. The result of the nationwide aptitude test in mathematics are normally distributed with a mean of 70 and a standard deviation of 5. Find the raw score such that 60% of the cases are below it and case above it.

Find the area that corresponds to each of the following z-score values.

1. z = 2.86

2.  = -0.91

3. z = -1.6

4. z = 1.32

5. z = -2.18

1. Given the data 6, 9, 12, 15, 16, 19, 22. Construct a sampling distribution of the sample mean without replacement and repetition by selecting 2 samples at a time.

A class consists 8 boys and 16 girls of which half the boys and haf the girls have blood group B. A student is selected at random what is the probability that the student is a boy or has B blood group

Solve the following LP problem by graphical method: Maximise Z = 300X1 + 700X2

Subject to the constraints: X1 + 4X2 ≤ 20 2X1 + X2 ≤ 30 X1 + X2 ≤ 8 And X1, X2 ≥ 0

A firm manufactures two products; the net profit on product 1 is Birr 3 per unit and Birr 5

per unit on product 2. The manufacturing process is such that each product has to be

processed in two departments D1 and D2. Each unit of product1 requires processing for 1

minute at D1 and 3 minutes at D2; each unit of product 2 requires processing for 2 minutes

at D1 and 2 minutes at D2. Machine time available per day is 860 minutes at D1 and 1200

minutes at D2. How much of product 1 and 2 should be produced every day so that total

profit is maximum. (solve with graphical method

Getting a defective item when two items are randomly selected from a box of two defective and three non-defective items       

if (p ∧ q) then (q ∨ r)

¬ (p → q) ≡ p ∧ ¬q

 Let f be the function from {a, b, c} to {1, 2, 3} such that f(a) = 2, f(b) = 3 and

f(c) = 1. Is f invertible, and if it is, what is it’s inverse?

Find the mean of the probability distribution of a random variable X which can take only the values 2, 4, 5, and 9 given the respective probabilities; 9/20, 1/20, 1/5, 3/10.