7. Rosita started riding her bike 3 km to her friend Gena's place at exactly the same time Gena started skating to Rosita's house. Gena, of course, wasn't home, so Rosita rode
back home. The two girls arrived at Rosita's house at the same time. It took Rosita
30 minutes to ride to Gena's and back. How fast did Gena skate?

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.

80cm/s.

24cm/s.

53.3cm/s.