Question

HELP!

Answer 1

One is twice the starting material than the other and has twice the final material. Think about that. If you lose 50% of something and start with 100 and 50 then you would have 50 and 25.

Answer 2

A "half-life" is the amount of time it takes for the material to decay and lose 50% of the starting material. In the same amount of time both substances have lost an equal proportion of material.

Answer 3

So a?

Answer 4

@TTP yes.