Jenny's Free Throws

worthawholebean

At each basketball practice last week, Jenny made twice as many free throws as she made at the previous practice. At her fifth practice she made $48$ free throws. How many free throws did she make at the first practice?

$\textbf{(A)}\ 3\qquad\textbf{(B)}\ 6\qquad\textbf{(C)}\ 9\qquad\textbf{(D)}\ 12\qquad\textbf{(E)}\ 15$

**Posted:** Mon Jan 05, 2009 9:24 am

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Bugi

Geometric progression, so on the first practice it was: $\frac{48}{2^{5-1}}=3$

**Posted:** Mon Jan 05, 2009 9:47 am

triplebig · Riemann Hypothesis Offline Joined: 04 Apr 2008 Posts: 250

She made $x$ free-throws on her first practice.

First day: $x$
Second day: $2x$
Third day: $4x$
Fourth day: $8x$
Fifth day: $16x$

From the problem, $16x=48\Leftrightarrow x=3$

Answer: Letter (A)

**Posted:** Mon Jan 05, 2009 9:50 am

Z-coli

To speed this one up, you can just use the answers as a guide. Letter $(E), (D),$ and $(C)$ are all way too big, so now all we have to look at is $(A)$ and $(B)$ . After a quick check, we see that $\boxed {(A)}$ is definitely the answer $(3 \bullet 2^{4}=48)$ .

**Posted:** Mon Jan 05, 2009 1:55 pm

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mathlinks1993 · New Member Offline Joined: 04 Nov 2009 Posts: 1

Simplest way:

Day5:48
Day4:24
Day3:12
Day2:6
Day1:3

So the answer is A.

**Posted:** Wed Nov 04, 2009 6:05 pm