You are looking for something "if A, then B" equals "if B, then A".
The only one that satisfy the above is B.
Answer:
29
Step-by-step explanation:
For the two digit numbers it has to end in a zero or five and be greater than 9 and below 100.
There are 18 multiples of 5 that are 2 digit
For multiples of 7... it's easier to write it out because the total number will will less than 20.
There are 13 multiples of 7 that are 2 digits
Now you have to subtract the multiples of 7 that end in a 0 or 5
That give you 11 multiples
Add 11 and 18 to get 29
I think I could help you
Have fun and feel free to ask me something new.
Or we can prove some properities without calculating by details
