Bunuel
If Juan takes 11 seconds to run y yards, how many seconds will it take him to run x yards at the same rate?
(A) 11x/y
(B) 11y/x
(C) x/(11y)
(D) 11/(xy)
(E) xy/11
Let's solve the question using the
input-output approach.
For example, let's let y =
22This means that Juan takes 11 seconds to run
22 yards, which means his speed is 2 yards per second.
From here, if we let x =
10, then the question is asking,"how many seconds will it take Juan to run 10 yards at the same rate (of 2 yards per second)?"
Well, at that speed, it will take Juan
5 seconds to run
10 yards.
In other words, if we INPUT y =
22 and x =
10, then the answer (the OUTPUT) to the question is
5.
Now we'll plug y =
22 and x =
10 into the answer choices and see which one yields the OUTPUT of
5 (A) 11x/y = (11)(
10)/22 =
5 GREAT!
(B) 11y/x = (11)(
22)/
10 =
something other than 5 ELIMINATE B
(C) x/11y = (
10)/(11)(
22) =
something other than 5 ELIMINATE C
(D) 11/xy (11)/(
10)(
22) =
1/20 ELIMINATE D
(E) xy/11 = (
10)(
22)/(11) =
20 ELIMINATE E
Answer: A
Cheers,
Brent