If the stress on your part is expected to be 150 MPa and the part has a strength of 200 MPa with a standard deviation of 10 MPa. What standard deviation could you allow in the stress the part will see under use? This part should have a reliability of 0.999 which corresponds to an X of 3.090 ( or a Z of -3.090 per table A-10 in your book). Enter your number in units of MPa (enter only a number).