this is quality control

An ALT is conducted using ten identical sample products by subjecting them to 180 C and recording the failure times. The observed failure time data are presented below (in hours). 2626, 2951, 4187, 493, 601, 1493,678, 974, 880, 4001 Assume that the failure time data exhibit an exponential distribution, please finish the tasks below. The normal operating temperature of this product is 30 C, and the acceleration factor is 50. a) What is the mean time to failure at normal operating condition? b) If the product is warranted for 200,000 hours, does this product meet the warranty requirement? Why? c) What is the reliability of this product operating at the normal conditions at time = 10,000 hours? d) If there are three more experimental samples, the observed failure time data are 4912, 5000+, and 5000+. The "+" sign indicates censoring time. What is the failure rate at normal operating conditions