The answer explanation to a GMAT Prep question reads as follows:
"... combining 1/5(N-1) = P - 1 and 1/4(N-2) = P, it follows that (N-1) = (N-2) - 1. This is a linear equation in N and can be solved for a unique value of N."
First of all, when I combine the first two equations, I get 13/10 = (1/20)N, which gives me N = 26. How are they getting the equation (N-1) = (N-2) - 1, and how is that a linear equation with a unique solution? Isolating N, we get 0 = -2, which is false.
It's been a long day, and perhaps I am missing something obvious. But right now I am quite perplexed by this.
Thanks
"... combining 1/5(N-1) = P - 1 and 1/4(N-2) = P, it follows that (N-1) = (N-2) - 1. This is a linear equation in N and can be solved for a unique value of N."
First of all, when I combine the first two equations, I get 13/10 = (1/20)N, which gives me N = 26. How are they getting the equation (N-1) = (N-2) - 1, and how is that a linear equation with a unique solution? Isolating N, we get 0 = -2, which is false.
It's been a long day, and perhaps I am missing something obvious. But right now I am quite perplexed by this.
Thanks
