Math Answers

1. Eddie borrows R12000 from Janet at the beginning of 2005, at a rate of 10% p.a. compound interest. At the end of each year, he pays back R500. How much must he still pay at the end of 2008? How much does he have to pay back altogether?

Eddie borrows R12000 from Janet at the beginning of 2005, at a rate of 10% p.a. compound interest. At the end of each year, he pays back R500. How much must he still pay at the end of 2008? How much does he have to pay back altogether?

The table below describes results from random selection of eight live births from eight different sets of parents. The random variable x represents the number of girls among the eight live births. Is 6 a significantly high number of girls out of 8 live births?

The probabilities that a customer buys 2,3,4,5 or 6 items in the convenience store a 0.32 0.12 0.23 0.18 and 0.15 respectively

Construct the probability distribution of random variables then draw the corresponding histogram.

Three coins are tossed. Let x be the random variables representing the number of heads that occur. Find the values of the random variable Z.

In a national achievement test, the mean was found to be 62 and the standard deviation was 10. The scores also approximate the normal distribution.

1. What is the minimum score that belongs to the upper 10% of the group?
2. What are the two extreme scores outside of which 5% of the group are expected to fall?
3. What is the score that divides the distribution into two such that 75% of the cases is below it?
4. Estimate the range of scores that will include-

a. the middle 50% of the distribution.

b. the middle 95% of the distribution.

F(x) = 6x² - 10x + 12

F(x) = 5x² -8x + 10

F(x) = x² + 9x - 4

Heights of the students in a class are given in the distribution below:

5' - 5'2"      11

5'2" - 5'4" 40

5'4" - 5'6"   25 .

Find:

1. Distribution