Jim walks 12 miles, then swims two miles. If he walks two miles per hour faster than he swims, and he finishes his exercise (both walking and swimming) in four hours, how fast does he swim ?

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

answer: 2530

hope this

c

step-by-step explanation: