Shruti0805 wrote:
Hi
mikemcgarry,
I took somewhere around 5 minutes to work out the solution! Had to use Pythagoras thrice and a bit of substitution. Is there a shorter, more elegant way to solve this? Would such questions appear on the actual test?
Thanks in advance
AbhiJung wrote:
I solved this problem rather quickly using the rule of Pythagoras i.e 3:4:5.
But since the diagram is not drawn to scale, is this method flawed?
Dear
Shruti0805 &
AbhiJung,
I'm happy to respond.
I came up with this problem on the fly, without much planning. I was inspired by another flawed problem here on GMAT Club.
AbhiJung, essentially you guessed in the dark, and the flaw of this problem was that an uninformed guess could lead to the right answer. In general, if all you know is that a right triangle has a hypotenuse of length 5, the GMAT will punish you for blindly assuming that the triangle has to be a 3-4-5 triangle. Insofar as this problem did not punish this poor approach, this is not really a good GMAT question.
Nevertheless,
Shruti0805, for the harder questions on the Quant section, the GMAT absolutely could give you a question that involves a holiday festival of algebra. Many harder Quant questions have an elegant solution, but one of the many things the Quant section assesses, at the upper level, is having the stomach to handled an ocean of algebra--and having the skill to wade through it efficiently and purposefully. Any question that separates those with what it takes to solve a problem from those who don't is a useful question, in terms of formal statistically question design. If what this question takes is doing a lot of algebra, then the right question is not about how to avoid that, but instead how to do it all efficiently and strategically. The respond of
Old in this thread was a particularly skillful use of algebra. If you had to use the Pythagorean Theorem three times, this suggests that you did not pursue the most strategic route to the solution.
Does all this make sense?
Mike
_________________
Mike McGarry
Magoosh Test PrepEducation is not the filling of a pail, but the lighting of a fire. — William Butler Yeats (1865 – 1939)