Aprogram is seeded with 30 faults. during testing, 21 faults are detected, 15 of which are seeded faults and 6 of which are indigenous faults. what is the mill's estimate of the number of indigenous faults remaining undetected in the program?

Awall of 0.5m thickness is to be constructed from a material which has average thermal conductivity of 1.4 w/mk. the wall is to be insulated with a material having an average thermal conductivity of 0.35 w/mk so that heat loss per square meter shall not exceed 1450 w. assume inner wall surface temperature of 1200°c and outer surface temperature of the insulation to be 15°c. calculate the thickness of insulation required.