Barry buys a new washing machine. The value of the washing machine depreciates by 20% each year.
(a)
Barry says 'after 5 years the washing machine will have no value'.
Barry is wrong. Explain why.
Barry wants to work out the value of the machine after 2 years.
(b)
By what single decimal number should Barry multiply the value of the machine when new?

Marco is studying a type of mold that grows at a fast rate. he created the function f(x) = 345(1.30)x to model the number of mold spores per week. what does the 1.30 represent? how many mold spores are there after 4 weeks? round your answer to the nearest whole number. 1.30 represents the number of mold spores marco had at the beginning of the study; 985 mold spores 1.30 represents the number of mold spores grown in a given week; 448 mold spores 1.30 represents the 30% rate of weekly growth; 345 mold spores 1.30 represents the 30% rate of weekly growth; 985 mold spores

What is the definition of exponential decay?

What is the radius of a circle with an area of 78.5 cubic inches? use 3.14 for pie