Andy took a bus and then walked from his home to downtown. For the first 16 hour, the bus drove at an average speed of 15
km/h. For the next 0.4 hours, he walked at an average speed
of 4.5 km/h. What was the average speed for the whole
journey?

Given :

Speed of bus for first 16 hours is , u = 15 km/h .

Distance he walked for next 0.4 hour is , v = 4.5 km/h .

To Find :

The average speed for the whole  journey.

Solution :

Average speed is given by :

Therefore , the average speed of the journey is 14.74 km/h .

Hence , this is the required solution .

the force on the thing and the distance the force moves the thing

answer: at 24 february, 2014 the population gets twice of its initial population.

explanation:

since we have given that

the population for alpha city, t years after january 1, 2004 is given as

first we find out the initial population, i.e. t=0,

so, our quadratic equation becomes,

according to question, we have said that if the population has twice its initial population, then it becomes

so, time taken to reach this above mentioned population is given by

now, we know that time can't be negative so, we take t=9.149 years.

hence, at 24 february, 2014 the population gets twice of its initial population.