25 If it is planned to run bit no.21 what is the probability that this bit will drill 79 *.and 124 feet or greater respectively Footage Bit No. Drilled, ft N 1 69 2. 72 3 123 4 135 5 95 6 89 7 139 8 109 9 125 10 80 11 102 12 53 13 76 14 102 15 90 16 116 17 105 18 108 19 115 20 110 10% and 80%. 60% and 70%. III 80% and 10%. 25% and 95%