WEEK SIX
REVIEW OF FIRST HALF LESSONS
WEEK TWO
In a community, 10% of the people tested positive to the HIV virus. If 6 persons from the community
are selected at random, one after the other with replacement, calculate correct to four decimal places,
the probability that (i) exactly 5 (ii) none (iii) at most 2, tested positive to the virus.
WEEK THREE
The mean score of 200 students in an examination is 40 and the standard deviation is 8. if the scores
are assumed to be normally distributed, find the :
- Proportion of students obtaining more than 46
- Number of students scoring between 32 and 48.
WEEK FOUR
Coplanar forces 4N, 8N, 6N, 4N and 5N act at a point as shown in the diagram . If the 6Nforce act in the direction 0900 calculate the: (a) Magnitude of the resultant force (b) Direction of the resultant force
WEEK FIVE
A uniform plank PQ of length 8m and mass 10kg is supported horizontally at the end P and at point R. 3 metres from Q. A boy of mass 20kg walks along the plank starting from P. If the plank is in equilibrium, calculate the
a. reaction at P and R when he has walked 1.5 metres
b. distance he had walked when the two reactions are equal. (take g = 10ms-2)