Problem Solving

A plot is in the shape of a right-angled triangle whose shorter sides measure 78.8 meters and 62.4 meters 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

[spoiler]OA=D[/spoiler]

Source: e-GMAT

Let opposite = o = 78.8 metres
Let adjascent = a = 62.4 metres
Let hypotenuse = h = ??
Given that an insect covers 100 inches in 1.79 minutes and 1 meter = 39.37 inches
$$o=39.37\cdot78.8=3102.36\approx3102\ inches$$
$$a=39.37\cdot62.4=2456.69\approx2457\ inches$$
$$clo\sin g\ pythagoras,\ h=\sqrt{o^2+a^2}$$
$$\ h=\sqrt{\left(3102\right)^2+\left(2457\right)^2}$$
$$\ h=\sqrt{9622404+6036849}$$
$$\ h=\sqrt{15,659,253}$$
$$\ h=3957.18\approx3957\ inches$$
Perimeter of a triangle = o + a + h
= 3102 + 2457 + 3957
=9516 inches
Insect covers 100 inches in 1.79 minutes
It will cover 9516 inches in t
$$t=\frac{9516\cdot1.79}{100}$$
$$t=170.34\approx170\min utes$$
If it takes 170 minutes to cover the perimeter then it will take 170 minutes to get back to the starting point
Converting 170 minutes to hours:
$$=>\frac{170}{60}=2.83\approx3hours$$
$$Answer\ =\ D$$