Home > Problem of the Week > Archive List > Detail

<< Prev 3/20/2011 Next >>

CSI Case #4051

Detectives investigating a crime find a bullet hole in a wall at a height of 7 feet 6 inches above the floor. The bullet passed through the wall at an entrance angle of 56o. Gill Tea, who stands 5 feet 6 inches tall, told the detectives he had fired the gun when he was standing 9 feet from the wall.

Using mathematics, explain why Gill is probably lying...assuming no carom was involved.


Source: Variation of Problem 18 (pg 522) in Carmant & Saunders' Mathematics for the Trades," (1996)

Hint: Draw a picture...now calculate the height of the gun when it was shot.


Solution Commentary: For the "assumed facts" to fit, the triangle of interest suggests that the gun when fired was 6 inches from the floor. Gill Tea must be lying. Book'm Matho!