For this to be easier, we know the date is February, since we are subtracting the 6 months. So let's start with February 13th, and subtract a week. One week is equal to 7 days, so 13-7= 6. We're now on February 6th, and we still have to subtract 2 days. 6-2=4, so we are at our date. A, Howard planted a tree in his front yard on February 4th.
The probability is 3/14. There are 2 multiples of 4 in 14, which is 8 and 12. There is only 1 multiple of 6 in 14 which is 12. 1+2=3. It is possible outcomes over total outcomes so 3/14.