The probability of the first event with x possible outcomes is equal to x/30. Also, the probability of the second event with y possible outcomes is y/29.
(1) P of 2 digit number, 21/30 P that the number is 4 is 1/29 Multiplying both probabilities will give us 7/290
(2) P that number is 19 is 1/30 P that the number is multiple by 4 is 6/29 The answer is 1/145
(3) P that number is 24 is 1/30 P that number is less than 15 is 14/29 The answer should be 7/435.
(4) P that number 1st number is perfect square is 5/30 P that second number is perfect square is 4/29. The answer is 2/87.
The number is = 10x+y if reverse the digits, the number is: 10y+x The sum fo its digits is = x+y=5 I suggest this system of equations: (10y+x)-(10x+y)=27 ⇒9y-9x=27 x+y=5 We can solve this system of equations by equaliztion method x=5-y
