If you weigh 100 pounds on Earth how much pounds would you weigh on Mars?

Gravitational acceleration at Mars' surface = 3.7 m/sec2 = (3.7/9.8) = 0.3776 of its value at earth's surface.

An object that weighs 115 on earth would weigh [ 115 x (3.7/9.8) ] = 43.418 on Mars. (rounded)