In june, Mr chen's students read 40 books. in july the read 30 books. what is the percent increase or decrease in the number of books they read? A. 20% increase
B. 25% decrease
C. 20% decrease
D. 40% decrease

In the diagram, the measure of angle 9 is 85° which angle must also measure 85°?

Acertain population of bacteria demonstrates exponential growth doubles in size every 4 days. how long will it take the population to triple in size?

How many of the 250 grandparents in the population would you expect to prefer online shopping with merchant a? merchant a: 4 merchant b: 6 merchant c: 2 merchant d: 3 other: 5 none: 5 answer choices: a.about 4 b.about 8 c.about 40 d.about 21