Express in scientific notation - immediately

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?

$30 to spend on dinner tax and gratuity at mos restaurant rax is 6% and they give a 15% tip on the total bill after taxes thier dinner cost $21 which statement correctly explains wether andrew and kate have enough money to pay their bill

The hockey team has been great! in 2008 they won 20% more games than in 2007. in 2009 they won 50% more games than in 2008. what was their overall percentage increase from 2007 through 2009?