You and a Friend Live 4 Miles Apart (On the Same

Multiple Choice

You and a friend live 4 miles apart (on the same "east-west" street) and are talking on the phone.You hear a clap of thunder from lightning in a storm,and 16 seconds later your friend hears the thunder.Find an equation that gives the possible places where the lightning could have occurred.(Assume that the coordinate system is measured in feet and that sound travels at 1100 feet per second. )
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A) $\frac { x ^ { 2 } } { 34,073,600 } + \frac { y ^ { 2 } } { 77,440,000 } = 1$
B) $\frac { x ^ { 2 } } { 34,073,600 } - \frac { y ^ { 2 } } { 77,440,000 } = 1$
C) $\frac { y ^ { 2 } } { 77,440,000 } - \frac { x ^ { 2 } } { 34,073,600 } = 1$
D) $\frac { x ^ { 2 } } { 77,440,000 } - \frac { y ^ { 2 } } { 34,073,600 } = 1$
E) $\frac { x ^ { 2 } } { 77,440,000 } + \frac { y ^ { 2 } } { 34,073,600 } = 1$