Set up appropriate systems of two linear equations and solve the systems algebraically. All data are accurate to at least two significant digits.

An underwater (but near the surface) explosion is detected by sonar on a ship 30 s before it is heard on the deck. If sound travels at 5000 ft/s in water and 1100 ft/s in air, how far is the ship from the explosion? See Fig. 5.31.

30 s fee............ 5000 ft/s Fig.5.31 1100 ft/s -