What is the minimum number of seismograph stations needed to determine precisely where an earthquake has occurred?

There are 4 red balls, 6 white balls, and 3 green balls in a bag. if one ball is drawn from the bag at random, what is the probability that it is not white?

People keep spending additional units of a particular resource on a want until their marginal benefit is  decreasing withgreater thanless thannot affected by  their marginal cost.

In russia which of these challenges affects the transportation of both petroleum products and other goods?