need help with math questions (sat prep)

<p>I don't know how to do this level 5 question (nor do i really understand what its describing)</p>

<p>1) The 6 cabins at a camp are arranged so that there is exactly 1 straight path between each 2 of them, but no 3 of them are on a straight path. What is the tottal number of such straight paths joining these cabins?</p>

<p>2) John and Paul can each weed 1/4 of their garden in an hour, and their father can weed 1/3 of the garden in an hour. If all three work together at their respective rates, how many hours will it take to weed the garden?</p>

<p>A) 1
B) 1.2
C) 1.25
D) 1.4
E) 1.7</p>

<p>3) Different positive four-digit integers are to be formed by using each of hte digits 5,6,7 and 8 just once in each integer. How many such integers can be formed if the digits 7 and 8 must be next to each other?
a) six b) eight c) twelve d) eighteen e) twenty-four</p>

<p>answers: 1) 15 2) B) 1.2 3) C -12</p>

<p>bump bumpy bumpy buasneoaijwa</p>

<p>3) Possible combos
See the pattern as i go along? There are 12
(if you understand the pattern, it'll go faster; if not, there's no problem in writing it out as long as you get the answer</p>

<p>1, Start with a camp:
camp 1 has 5 straight paths to the rest
camp 2 has 4 straight paths (because one straight path to camp 1 has already been counted)
camp 5 has 1 straight path
camp 6 is left with no straight path (it's connected with all other camps) </p>

<p>so you have : 5+4+3+2+1+0=15</p>

<p>2, let's call the time needed for the 3 to do the whole thing: X
You have: X * (1/4 +1/4 +1/3) = 1 --> X=6/5=1.2 hours</p>