Question

Contagious diseases can spread quickly. Suppose 3 people are ill during the first week of an epidemic, and each person who is ill spreads the disease to five people by the end of the next week. By the end of the 8th week of the epidemic, how many people have become ill?

Answer 1

1875

Explanation:

3x5 = 15

15x 5 = 75

75x 5 = 375

375 x 5 = 1875

1875 because at the end of the next week, which basically turns 8 weeks into 4, and the number of contaminants multiply by 5 each other week.