AAPL wrote: ↑

Wed Jan 20, 2021 9:20 am

E-GMAT

A plot is in the shape of a right-angle triangle whose shorter sides measure 78.8 meters and 62.4 respectively. If an insect takes 1.79 minutes to cover a distance of 100 inches, what is the approximate time that it will take to return to its starting point after covering the entire perimeter of the plot in one direction? (1 meter is approximately 39.37 inches)

A. 24 seconds
B. 4 minutes
C. 17 minutes
D. 3 hours
E. 290 hours

OA D

Solution:

We are given a right triangle with the length of its two legs. We need to determine the hypotenuse. Instead of finding the exact length of the hypotenuse, we can just approximate it (since we are approximating the time for the insect to go around the perimeter of the triangle anyway). By rounding 78.8 to 80 and 62.4 to 60, we see that the hypotenuse is approximately 100 meters.

Therefore, the perimeter of the triangle is approximately 80 + 60 + 100 = 240 meters. If we round 39.37 to 40, the perimeter of the triangle, in inches, is approximately 240 x 40 = 9600 inches. Finally, if we round 1.79 to 1.8, we can create the following equation, where x is the number of minutes it will take the insect to go around the perimeter of the triangle:

1.8 / 100 = x/9600

1.8 = x/96

x = 1.8 * 96 = 172.8 minutes.

We see that 172.8 minutes is closest to 3 hours (or 180 minutes); thus, choice D is the correct answer.

Answer: D