The wording of this question is a bit confusing... You can't write a sequence in sigma notation, but rather a series or sum. I think the question is asking you to write the sum of the sequence,
which would be
in sigma notation.
To do this, notice that the denominator in each term is a power of 2, starting with 
and ending with 
. So in sigma notation, this series is
What you want is P(6∩1) or P(1∩6) or P(2∩5) or P(5∩2) or P(3∩4) or P(4∩3).
The events of rolling the dice are independent (i.e. they don't affect one another) so:
E.g.
P(6∩1) = P(6) * P(1)
P(2∩5) = P(2) * P(5)
The probability of getting a given number on a roll is 1/6 for both dice.
So:
P(6∩1) = 1/6 * 1/6 = 1/36
This is the same for any arrangement of numbers you could get from rolling two dice.
So, we can see that there are 6 arrangements of numbers that will give a sum of 7 and so that is 6 * 1/36 = 6/36 = 1/6
The request is to find the intersection of the two sets. By definition, the intersection of two sets is another set, composed by all the elements appearing in both sets.
In other words, 
is the set of all elements that P and Q have in common.
P contains all the numbers from 0 to 9, V contains all the odd numbers between 1 and 19. So, their intersection will be the odd numbers between 0 and 9, i.e.
Ben is taller
Ben: 5 5/16 feet = 1.61925 meters
Marcus: 5 7/24 feet = 1.6129 meters
X=14/5 if you want solution here:
Use the commutative property to reorder the terms: 2x=14-3x
Move the variable to the left - hand side and change sign: 2x+3x=14
Collect like terms: 5x=14
Divide both sides of the equation by 5: x=14/5
