Question

There are 20 locks and their 20 keys but they are mixed up and the attendant does not know which key matches which lock. He places each key with a lock at random, then what is the probability that atleast one of locks 1 and 5 will find it's key

Answer 1

Answer:

20 + 20 = 40. we can remember 40 is 40 x. then x = 40 / 20 then the answer is 20 so we can remember 20 is 20x then 5+1 = 6-1=1 then 20/5 answer is 4 then the keys are 4+5+1= 10

Step-by-step explanation:

hope it helps