BTGmoderatorLU wrote: ↑

Thu Jun 01, 2023 4:53 pm

Source: Princeton Review

If two projectiles are launched at the same moment from \(1320\) miles apart and travel directly towards each other at \(480\) miles per hour and \(510\) miles per hour, respectively, how many minutes will it take for them to meet?

A. \(40\)
B. \(44\)
C. \(80\)
D. \(88\)
E. \(90\)

The OA is C

We have two projectiles traveling towards each other at different speeds, 480 mph and 510 mph.

When two objects move towards each other, their relative speed is the sum of their individual speeds. So, the relative speed of the two projectiles is 480 + 510 = 990 miles per hour.

They start 1320 miles apart and are closing that distance at 990 miles per hour. To find out how long it takes for them to meet, we need to divide the total distance by their relative speed.

Time = Distance / Speed = 1320 miles / 990 mph = 1.333 hours

However, the question is asking for the time in minutes. Since there are 60 minutes in an hour, we multiply the time in hours by 60 to convert it to minutes:

1 and a 1/3 of 60 minutes + an extra 20 minutes = 80 minutes

So, it will take them 80 minutes to meet, which is answer choice (C)