Twelve people join hands for a circle dance. in how many ways can they do this?

Awindow washer cleans 42 windows in 2 hours. at this rate, how many windows did he clean in 180 minutes.

Without any equipment, you can see stars that are 2{,}800{,}0002,800,0002, comma, 800, comma, 000 light-years away. by looking through a small telescope, you can see stars that are 3{,}112{,}000{,}0003,112,000,0003, comma, 112, comma, 000, comma, 000 light-years away. approximately how many times as far can you see using a small telescope as without any equipment?

Ken earned $128 from his part-time job this summer. he spent 25% of his money on games. he is going to donate 1/6 of the remaining money to charity. how much money will the charity receive?