What is the least common multiple of 21 and 30?

What is the solution to the equation 9^(x+1) =27

In a sale there is 25% of all prices a chair costs £45 in sale how much was it before the sale

Martha is training for a duathlon, which includes biking and running. she knows that yesterday she covered a total distance of over 55.5 miles in more than than 4.5 hours of training. martha runs at a speed of 6 mph and bikes at a rate of 15.5 mph.