10 points giving for answer

Prove that the sum of two consecutive exponents of the number 5 is divisible by 30.if two consecutive exponents are 5n and 5n + 1, then their sum can be written as 30.

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?

Noel is hoping to make a profit (in $) on the school play and has determined the function describing the profit to be f(t) = 8t – 2654, where t is the number of tickets sold. what does the number 8 tell you?