If you already know the Algebraic solution to this Problem, when you REVIEW, YOU SHOULD TRY ANOTHER APPROACH!This is a Variable in the choices type question.so this is a great question to TEST IT! Try your own number.So let's try some nice small numbers:
The speed z = 2,
The three sides:
1/ side P to Q >> x = 4,
2/ side Q to R >> y = 3 and
3/ thus the hypotenuse side P to R will be
5. Pythagorean triplet!!
(With enough official question practice the intuition to use smart number will develop)
Now we want to go: Q to R and then R to P.
Basically this means we want to go (3+5)=8 miles total. Our speed z is 2 miles per hour. So we will need total 4 hours.
So our Target value is 4
Let's find 4 when we plug in x=4, y=3 and z=2.
Taking a small glance in the answer choices, we can see all choices contain [√(x^2 + y^2)]
^^this is equal to [√(4^2 + 3^2)] = √25 = 5.
(A) 5/2 nope.
(B) 9/2 nope.
(C) (3+5)/2 = 4 BINGO!
(D) this is less than 1
(E) this is also less than 1.
DONE!
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