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you only can only buy six pencils and six erasers
Answer: c
Step-by-step explanation:

The rows add up to

, respectively. (Notice they're all powers of 2)
The sum of the numbers in row

is

.
The last problem can be solved with the binomial theorem, but I'll assume you don't take that for granted. You can prove this claim by induction. When

,

so the base case holds. Assume the claim holds for

, so that

Use this to show that it holds for

.



Notice that






So you can write the expansion for

as

and since

, you have

and so the claim holds for

, thus proving the claim overall that

Setting

gives

which agrees with the result obtained for part (c).
1) 0.927184
2) 0.615661
3) 0.383864
Step-by-step explanation:
the problem description is incomplete or wrongly copied.
we don't know the thickness of the boards, and we cannot understand what we need to calculate, and what the answer options are.