# Math Help - 2x2 System word problem?

1. ## 2x2 System word problem?

An underwater(but near the surface) explosion is detected by sonar on a ship 30s before it is heard on deck. If sound travels at 5,000 ft/s in water and 1,000 ft/s in air, how far is the ship from the explosion?

All I need is the equations and I'll be aright to go from their.

2. Let $t$ be equal to the time it takes to be heard by the sonar.

We then have that the time for it to be heard on deck is $t + 30$.

$v = \frac {d}{t}$

Therefore:

$d = vt$

And since the distances are equal:

$1000(t + 30) = 5000t$

Now solve for $t$ to get:

$4000t = 30000$

$t = 7.5$

Now just plug that into the equation $d = vt$ to get:

$d = 5000(7.5)$

$d = 37,500$ feet