<h3>
Answer: 39</h3>
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Explanation:
You can use the nCr formula shown below

where n = 39 and r = 1. However, you could also use the identity

which basically says there are n ways to pick 1 item if you are given a choice of n items. In this specific case, we have 39 items total, and there are 39 ways to pick one item.
Answer:
$3 for 1 book.
Step-by-step explanation:
1 thousand and 1 hundred means 1100.
In scientific notation, it's 1.1*10^3
I believe there is no such AP...
Recursively, this sequence is supposed to be given by

so that




has to be an integer, which means there are 4 possible cases.
Case 1:
and
. But

Case 2:
and
. But

Case 3:
and
. But

Case 4:
and
. But

The last pair.
Because 2*4/3*4=8/12