jesse may

A first-order reaction is 40% complete at the end of 50 minutes. What is the value of the rate constant (in min^-1)? A. 1.8 x 10^-2 B. 1.0 x 10^-2 C. 1.2 x 10^-2 D. 8.0 x 10^-3 E. none of these how would i approach this problem? i know that to find the ra...