Distance=speed times time
if they take the same time, we cal the time , t
b=bike speed
w=walking speed
bikedistnace=17=bt
walkdistance=9=wt
b is 4 more than w
b=4+w
we have
17=bt
9=wt
b=4w
ok so
multiply first equation by 9 and 2nd by 17
153=9bt
153=17wt
set equal
9bt=17wt
divide both sides by t
9b=17w
sub b=4+w for b
9(4+w)=17w
distribute
36+9w=17w
minus 9w both sides
36=8w
divide both sides by 8
4.5=w
he walks 4.5kph
Number of weeks in a year divided by 6, then multiply that answer by $108
Answer:
37.27% probability that he or she will have a heart attack.
Step-by-step explanation:
Bayes Theorem:
Two events, A and B.

In which P(B|A) is the probability of B happening when A has happened and P(A|B) is the probability of A happening when B has happened.
In this question:
Event A: Periodontal disease
Event B: Heart attack
Researchers discovered that 82% of people who have suffered a heart attack had periodontal disease, an inflammation of the gums.
This means that 
Only 33% of healthy people have this disease.
This means that 
Suppose that in a certain community heart attacks are quite rare, occurring with only 15% probability.
This means that 
If someone has periodontal disease, what is the probability that he or she will have a heart attack

37.27% probability that he or she will have a heart attack.