The two test teams test the same program independently and estimate the total number of errors in the program.

Question: Two test teams test the same one independently.ProgramThe first group found 25 errors, the second group found 30 errors, 15 of the errors found in the two groups are common, so we can estimate the total number of errors in the program is ()
A.25 B .30 C.50 D.60

Solution:

Answer 1:   (25 + 30-15)/(80%) = 50
Calculate the total number of bugs found in the two groups, and then according to the 2/8 Law of the test (that is, the test can only find 80% errors in the System)
Of course the result is 50.

Answer 2:
If the total number of errors is set to X, the probability of error A is 25/X, and the probability of error B is 30/X, the probability P (same as) of simultaneous error is 15/X.
Because P (a) * P (B) = P (Same), (25/x) * (30/X) = 15/x
Calculated x = 50