The bacteria in a petri dish grow in a manner such that each day the number of bacteria doubles. On what day will the number of bacteria be half of the number present on the 12th day?

An apple farm yields an average of 45 bushels of apples per tree when 21 trees are planted on an acre of ground. Each time 1 more tree is planted per acre, the yield decreases by 1 bushel (bu) per tree as a result of crowding. How many trees should be planted on an acre in order to get the highest yield? In order to get the highest yield, trees should be planted on an acre. OCEED

Initially, 10 people have an infection. The next day, every infected people infects one moreperson. If this pattern continues, how many days will it take for 1280 people to be infected?

The population of mice doubles every 12 hours. There are initially 4 mice. How many mice are there 3 days later?