A normal distribution, what percent of the data is within two standard deviations of the mean?

Lee has $1.75 in dimes and nickels. the number of nickels is 11 more than the number of dimes. how many of each coin does he have?

Ms.ortiz sells tomatoes wholesale. the function p(x)=-80x^2+320x-10, graphed below, indicates how much profit she makes on a load of tomatoes if she makes on a load of tomatoes if she sells them for 4-x dollars per kilogram. what should ms.ortiz charge per kilogram of tomatoes to make on a load of tomatoes?

Find the domain and range of the following function f(x) = 51x - 21+ 4