A Radar Pulse Sent Out to an Airplane at a Distance

Multiple Choice

A radar pulse sent out to an airplane at a distance of 24.1 km will return as an echo to the source in what time interval? (c = 3.00 × 10⁸ m/s)

A) 33.3 × 10−⁶ s
B) 80 × 10−⁶ s
C) 161 × 10−⁶ s
D) 40.2 × 10−⁶ s
E) ​482 × 10−⁶ s