Molly buys a necklace for $400 on her credit card, which charges 21% simple interest. How much interest will be added after 6 months? Write an equation and solve the problem.

Afactory adds 3 red drops and 2 blue drops of coloring to white paint to make each pint of purple paint. the factory will make 50 gallons of the purple paint. how many drops of red and blue coloring will the factory need in the 50 gallon batch of purple paint.

The measure of one angle of an octagon is two times smaller that of the other seven angles. what is the measure of each angle?

Suppose that in 2008 , 840,800 citizens died of a certain disease assuming the population of teh country is 399 miliion, what is the mortality rate in units of deaths per 100,000 people?