Math Problem Solver

A bin of 5 transistors is known to contain 2 defective transistors. The

transistors are to be tested, one at a time, until the defective ones are identified. Let N1

denote the number of tests made until the first defective is identified and let N2 denote

the number of additional tests until the second defective is identified. Find the joint

probability mass function of N1 and N2