Me solve this

10 elves each made 10 xylophones. each xylophone had 10 keys. they did this for 10 days. how many keys were made by the elves? show in exponential form and solve.

Two blends of tea are mixed to make a blend that will be sold at the fair. black tea sells for $2.20 per pound and orange pekoe tea sells for $3.00 per pound. how much of each should be used to obtain a 4lb blend selling for $2.50 per pound?

Which expression do you get when you eliminate the negative exponents of 4a^2 b^216a^-3 b

Two cars which are 40 miles apart start moving simultaneously in the same direction with constant speeds. if the speed of the car which is behind is 56 mph and the speed of the other car is 48 mph, how many hours will it take for the car which is behind to catch up the car ahead of it?