The selling price of a calculator is $15.00. if the markup is 25% of the dealers cost, what is the dealers cost of the calculator?

Given the choice between receiving $1.000.000 in one month or a single penny-doubled everyday for the period of one month; which option would you choice? show your work to support your answer. (assume that 1 month=30 days)

If the ratio of sum of the first m and n terms of an ap is m2 : n2 , show that the ratio of its mth and nth terms is (2m − 1) : (2n − 1).

Are the corresponding angles congruent? explain why or why not.