Problem: A powderman set a fuse for a blast to take place in 30 seconds. He ran away at a rate of 8 yards per second. Sound travels at the rate of 1080 feet per second. When the powderman heard the blast, he had run approximately:
Answer Choices:
A. 200 yd
B. 352 yd
C. 300 yd
D. 245 yd
E. 512 yd
Solution:
Since the times are inversely proportional to the rates,
30−tt=81080/3=45.∴t=30⋅4645 and d=8t=8⋅30⋅4645∼245.