Some problems from the rates section of Kaplan's book.

[colina]

I have not idea in how I can adreess these questions:

7. A marathon runner ran for two days. On the second day he ran 2 hours longer and at an average speed 1 mile per hout faster than he ran on the first day. If during the two days he ran a total of 64 miles and spent a total of 18 hours running, what was his average speed, in miles per hour, on the first day?
(A) 1.5
(B) 1.75
(C) 2
(D) 2.2
(E) 3
OA: (E)

EXTRA. Machine X and Machine Y are each used to manufacture 660 disposible diapers. It takes Machine X 10 hours longer to produce 660 disposible diapers than Machine Y. Machine Y produces 10 percent more disposible diapers per hour than Machine X. How many disposible diapers per hour does Machine X produce?
(A) 6
(B) 6.6
(C) 10
(D) 100
(E) 110
OA: (A)

[lime]

colina, this sub-forum is for math majors preparing for the subject test. Next time you would better post such questions in general GRE section.

1. Construct equation!

vt + (v+1)(t+2) = 64
t + (t+2) = 8

Solving both gives t=8, v=3.

2. Construct equation!

x*(t+10) = 660
y*t = 660
10y = 11x.

Solving for x, y gives y = 33/5, x = 6.

[colina]

Hey Lime: Thanks for the advice. I will post in the GRE quantitative section.
Thanks for the answers. They are very helpful.