Acertain type of elementary particle travels at a speed of 2.75ã108 m/s . at this speed, the average lifetime is measured to be 3.86ã10â6 s

From the given problem, there are only two parameters that are known: speed and time. From these two, I deduced that the obvious parameter relating them is the distance. Hence, I am guessing that what is asked here is the total distance a certain elementary particle has traveled in its lifetime. This can be determined by merely multiplying the speed with the lifetime of years.

Total distance = (2.75×10⁸ m/s)*(3.86×10⁻⁶ s)
Total distance = 1.0615×10¹⁵ meters