Answer:

Step-by-step explanation:
Set up the equation:
Since C(t) gives the number of cars purchased in the t-th year after 1998, then make the number of cars equal to 15 000 and solve for t - the year:
20t^2 = 15000
t^2 = 750
t = 
The year will be simply 1998 + 5 \sqrt{30}
Use the pythagoream theorem to check. a^2+b^2=c^2
a=15 b=36 c= 39
225+1296=1521
The equation is true so it is a right triangle.
Answer:
6.88
Step-by-step explanation:
Answer:
b = 55°
Step-by-step explanation:
The angle at the centre is twice the angle on the circle subtended by the same arc, then
a = 0.5 × 110° = 55°
Angles on the circumference subtended by the same arc are congruent, so
b = a = 55°
Answer:
The speed and time are directly proportional in that the higher the speed the lesser the time and vice versa.
The constant is the total distance which is 180 km
Step-by-step explanation:
Step one:
given data
The distance between the two cities is 180km
1.The distance was covered by a car at the rate of 50km/h
The time taken will be
velocity= distance/time
time= distance/velocity
time= 180/50
time= 3.6 hours
2.The distance was covered by a bus 45km/h
The time taken will be
velocity= distance/time
time= distance/velocity
time= 180/45
time= 4 hours
3.The distance was covered by a bicycle at 25km/h
The time taken will be
velocity= distance/time
time= distance/velocity
time= 180/25
time= 7.2 hours