In how many ways can the eight rooks be placed on an 8-by-8 chessboard so that no two rooks can attack one another?

The gades foundation and hbm corporation are eager to donate generously to their favorite charities. the gades foundation donated $250 in the first month, and each month afterward their cumulative donation total increases by 100$ the hbm corporation donated $64, in the first month, and each month afterward their cumulative donation total increases by 75%. in which month will the hbm corporation's cumulative donation total first exceed the gades foundations' cumulative donation total?

Mario has $14.35 left in his wallet. he spent $148.43 for tablecloths. then, he spent $92.05 for napkins. how much money did mario have in his wallet to start with?

2,10,-50 next two numbers geometric sequence