3) PRODUCT RELIABILITY - THE TREAD LIVES OF THE SUPERTITAN TIRES UNDER NORMAL DRIVING CONDITIONS ARE NORMALLY DISTRIBUTED WITH A MEAN OF 40,000 MILES AND A STANDARD DEVIATION OF 2000 MILES. a) WHAT IS THE PROBABILITY THAT A TIRE SELECTED AT RANDOM WILL HAVE A TREAD LIFE OF MORE THAN 35,000 MILES? b) IF FOUR NEW TIRES ARE INSTALLED IN A CAR AND THEY EXPERIENCE EVEN WEAR, DETERMINE THE PROBABILITY THAT ALL FOUR TIRES STILL HAVE USEFUL TREAD LIVES AFTER 35,000 MILES OF DRIVING.