Question

A 78 gram sample of Uranium loses half of its mass each year. What is the exponential equation? Please explain why A is the correct answer

A. y=78(0.5)^x


B. y=78(1.5)^x

Answer 1

A

Explanation:

The first answer is correct because we have a decay factor.

The sample is losing mass, so the number that is being multiplied by a power of x must be less than 1.

If the second answer were used, then the sample would be gaining mass.