Matt went mountain biking on a trail that is 13.5 miles each way. It took Matt 2 hours and 15 minutes to bike the 13.5 miles uphill. If it took 1 hour and 30 minutes to bike the 13.5 miles downhill back home, what was Matt's average speed for his round trip?

hello from mrbilldoesmath!

answer:

a(n) - a(n-1) -3

discussion:

this ones a bit interesting. given a(n) = 5 - 3n consider this:

a(n-1) = 5 - 3(n-1)

          = (5 - 3n) + 3             => but a(n) = 5 - 3n, the first term

          = a(n)   + 3                 => subtract 3 from both sides

a(n-1) -3 = a(n)  

or

a(n) - a(n-1) -3

you,

mrb

439400

step-by-step explanation:

130^2 = 16900

16900*26 = 439400