
therefore, the Correct choice is d) 15
Answer:
The required probability is, 0.78
Step-by-step explanation:
There are, (52 - 13) = 39 cards which are not spade
5 cards can be chosen from the deck of 52 cards in
ways
and out of these 5 choices, none of them will be spade in,
ways
So,
P(None of the chosen cards is spade)
= 

Hence,
P(out of these 5 choices, at least one card is spade)

= 0.78
Henry has to wrap five presents for a birthday party and has a length of ribbon to make bows for the presents. He cuts the ribbon into eight equal lengths and uses five of the pieces. With the remaining length of ribbon he is able to make six bracelets to give away at the party
This is a geometric sequence because each term is twice the value of the previous term. So this is what would be called the common ratio, which in this case is 2. Any geometric sequence can be expressed as:
a(n)=ar^(n-1), a(n)=nth value, a=initial value, r=common ratio, n=term number
In this case we have r=2 and a=1 so
a(n)=2^(n-1) so on the sixth week he will run:
a(6)=2^5=32
He will run 32 blocks by the end of the sixth week.
Now if you wanted to know the total amount he runs in the six weeks, you need the sum of the terms and the sum of a geometric sequence is:
s(n)=a(1-r^n)/(1-r) where the variables have the same values so
s(n)=(1-2^n)/(1-2)
s(n)=2^n-1 so
s(6)=2^6-1
s(6)=64-1
s(6)=63 blocks
So he would run a total of 63 blocks in the six weeks.