Two Different Running Shoe Manufacturers Market Running Shoes to First $\frac { 50 } { 17 }$

Two different running shoe manufacturers market running shoes to first time marathon runners.Swift claims a mean shoe life of 600 km,while Enduramax claims a shoe life of 650 km.If the standard deviation for both shoes is 51 km,which shoe would you purchase before starting your marathon training (where you figure to run 500 km) ? Explain.

A) Swift.Swift shoes are - $\frac { 50 } { 17 }$ standard deviations from the mean while Enduramax shoes are - $\frac { 100 } { 51 }$ standard deviations from the mean.
B) Enduramax.Enduramax shoes are - $\frac { 50 } { 17 }$ standard deviations from the mean while Swift shoes are - $\frac { 100 } { 51 }$ standard deviations from the mean.
C) Swift.I only need to run 500 km and the Swift will last 100 km beyond that.
D) Enduramax.Enduramax shoes are - $\frac { 100 } { 51 }$ standard deviations from the mean while Swift shoes are - $\frac { 50 } { 17 }$ standard deviations from the mean.
E) Swift.Swift shoes are - $\frac { 100 } { 51 }$ standard deviations from the mean while Enduramax shoes are - $\frac { 50 } { 17 }$ standard deviations from the mean.