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GMAT PREP ? (TableSpoons)

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GMAT PREP ? (TableSpoons)

by dferm » Sun May 04, 2008 11:12 am

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3 teaspoons = 1 tablespoon
4 tablespoons = 1/4 cup

According to the information above, how many teaspoons are equal to 3/8 cup?

A. 3
B. 4
C. 9
D. 12
E. 18

Please explain....


I got this question correct by making an educated guess but need a little light on this problem..

Thanks.
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by ksh » Sun May 04, 2008 11:54 pm
Try backsolving
1/4 cup= 4tablespoon =>3/8 cup=3/2*1/4 cup=6 tablespoons.
Now, 1 tablespoon=3teaspoon, => 6 tablspn=18 tspn.

Is it clear?
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by AleksandrM » Mon May 05, 2008 9:35 am
Or you can you use algebra.

First step is to multiply 3 by 4 to get 12 tea spoons per 1/4 cup.

Then just set up an equation:

12/( 1/4 ) = x/( 3/8 ) [if there are 12 tea spoons in one-fourth of a cup, then how many tea spoons will there be in three-eigths of a cup]

First solve each side of the equal sign 12 * 4 = 48 and 8/3 * x = 8x/3

48 = 8x/3 [multiply both sides by 3]

144 = 8x [solve for x]

x = 18 I believe that this is quicker and is more intuitive than backsolving. Backsolving, however, is still a good way to go with some other problems when it is quicker than algebra.
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by Jeff@TargetTestPrep » Thu Aug 30, 2018 5:00 pm
dferm wrote:3 teaspoons = 1 tablespoon
4 tablespoons = 1/4 cup

According to the information above, how many teaspoons are equal to 3/8 cup?

A. 3
B. 4
C. 9
D. 12
E. 18
We are given the following:

3 teaspoons = 1 tablespoon

4 tablespoons = 1/4 cup

We need to determine how many teaspoons are equal to 3/8 cup. Let's first convert 3/8 cup to tablespoons:

3/8 cups x 4 tablespoons/(1/4) cup

3/8 x 16 = 6 tablespoons

Next we can convert 6 tablespoons to teaspoons:

6 tablespoons x 3 teaspoons/1 tablespoon = 18 teaspoons

Alternate Solution:

We see that 4 tablespoons = 12 teaspoons = 1/4 cup. To determine the number of teaspoons equal to 3/8 cup, we can set up a proportion:

12 / (1/4) = x / (3/8)

36 / 8 = x / 4

36 = 2x

x = 18 teaspoons

Answer: E

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by [email protected] » Mon Sep 03, 2018 7:43 pm
Hi All,

We're told that 3 teaspoons = 1 tablespoon and 4 tablespoons = 1/4 cup. We're asked for the number of teaspoons that are equal to 3/8 cup. This question is a big 'unit conversion' question and includes a big 'design shortcut' that you can use to avoid most of the math.

To start, since 1/4 cup = 4 tablespoons and 1 tablespoon = 3 teaspoons, we know that 1/4 = (4)(3) = 12 teaspoons. Since 3/8 is greater than 1/4, we know that 3/8 of a cup is equal to MORE than 12 teaspoons. There's only one answer that matches...

Final Answer: E

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Contact Rich at [email protected]
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GMAT PREP ? (TableSpoons)

by fskilnik@GMATH » Wed Sep 05, 2018 6:56 am
dferm wrote:3 teaspoons = 1 tablespoon
4 tablespoons = 1/4 cup
According to the information above, how many teaspoons are equal to 3/8 cup?
A. 3
B. 4
C. 9
D. 12
E. 18
Please explain....
\[3\,\,{\text{teaspoons}}\,\,\,\, \leftrightarrow \,\,\,\,1\,\,\,{\text{tablespoon}}\]
\[4\,\,{\text{tablespoons}}\,\,\,\, \leftrightarrow \,\,\,\,\frac{1}{4}\,\,\,{\text{cup}}\,\,\,\,\,\]
\[\frac{3}{8}cup\,\,\, = \,\,\,\,?\,\,\,{\text{teaspoons}}\]
\[\frac{3}{8}cup\,\,\,\left( {\frac{{4\,\,{\text{tablespoons}}}}{{\frac{1}{4}\,\,\,{\text{cup}}}}\,\,\begin{array}{*{20}{c}}
\nearrow \\
\nearrow
\end{array}} \right)\,\,\,\,\left( {\frac{{3\,\,{\text{teaspoons}}}}{{1\,\,\,{\text{tablespoon}}}}\,\,\begin{array}{*{20}{c}}
\nearrow \\
\nearrow
\end{array}} \right)\,\,\,\, = \,\,\,\frac{{3 \cdot 4 \cdot 4 \cdot 3}}{{8 \cdot 1}} = 18\,\,\,\,\,\,\,\,\,\left[ {{\text{teaspoons}}} \right]\]

This is a nice example of UNITS CONTROL technique, one of our most powerful tools!

(Arrows indicate licit converters.)

The above follows the notations and rationale taught in the GMATH method.
Fabio Skilnik :: GMATH method creator ( Math for the GMAT)
English-speakers :: https://www.gmath.net
Portuguese-speakers :: https://www.gmath.com.br
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