Question 999098
Probability 2 have bad brakes
It can be the first and second or any other combination of two out of 5.  There are 10 such combinations.
The probability of the first and second is (7/17)(6/16)(10/15)(9/14)(8/13)
One does not have to compute each of the 10.  They will all have the same denominator and the same numbers will be in the numerator, just not in the same order.
Numerator is 30240, and it occurs 10 times.
Denominator is 742560
302400/742560 = 0.4072