I'm working on a couple of SAT math programs for school, and I have trouble figuring some out.
1. Joe is 3 years younger than Kate. If n represents Nora's age now, what was Kevin's age 4 years ago, in terms of n?
A. N + 7
B. N + 1
C. N - 1
D. N - 4
E. N - 7
2. If (x + y)^2 - (x - y)^2 = 84 and x and y are positive integers, which of the following could be a value of x + y?
Thanks so much in advance!
SAT Math? - bobpursley, Sunday, October 14, 2007 at 10:02pm
1. Not possible to solve. Too many kids named.
2. You have a diference of two squares, it factors to (x+y-x+y)(x+y+x-y) which reduces to 2y*2x=4xy or then solve for x,y
xy=21 and 7 and 3 fit that real nicely.