Option B is a better option.
Step by step:
I divided 40/6.29 and got about 6.3.
I divided 24/3.89 and got about 6.1.
Which is less, 6.3 or 6.1?
If you said 6.1 you are correct, so option B has a less cost, making it a better option.
Answer: A. 
Step-by-step explanation:
Total digits on keypad = 5
According to permutation,
If repetition of digits is not allowed then the number of 5-digits passwords can be formed = 5!
= 5 x 4 x 3 x 2 x 1 [n!=n x (n-1) x (n-2)x ... x 1]
=120
The probability that someone guesses the correct code = 

Hence, the correct option is A.
<span>There are 8,904 cycles per minute. This would be determining the amount of cycles per second, which is 148.4. After you know the amount per second, you can then multiply it by the time, which in this case is 60 seconds, or 1 minute. 148.4 cycles per second multiplied by 60 seconds is 8,904 cycles.</span>
<span>5x+2 = 77
5x = 75
x = 15</span>
First of all we need to convert the 3 yards to inches, So 3 * 12 = 36
36 / 16 = 2.25
I hope this helps :)