Answer: 
Step-by-step explanation:
Given : The total number of cards in a deck = 52
Number of red cards = 26
There are two types of red cards : diamond and heart.
Number of diamond cards = 13
The probability that the first card is a diamond :-

Since diamond is also a red card.
Now, the total cards left = 51
The number of red cards left = 12
The probability that the second card is a red card (without repetition) is given by :-

Now, the probability of choosing a red card for the second card drawn, if the first card, drawn without replacement, was a diamond :-

Answer:
708meters
Step-by-step explanation:
Given data
Lenght = 274meters
Width= 80 meters
The expression for the perimeter is
P= 2L+2W
substitute
P= 2*274+ 2*80
P= 548+160
P= 708 meters
Hence the perimeter of the block is 708meters
Speed =wavelength x frequency
= 2x1.5 = 3m/s