If there are 12 entries in the trifecta race, how many tickets must you purchase to guarantee a win?

For one history test, keith had to answer 40 questions. of these 40 questions, keith answered 28 of them correctly. what percent did keith get on his history test? round your answer to the nearest tenth if necessary

Prove that the value of the expression 7^8–7^7+7^6 is divisible by 43.

Two airplanes start at the same place and travel in opposite directions,one at 395 miles per hour and the other at 422 miles per hour. how many hours will it take for the planes to be 2451 miles apart?