Question

A scientist studies a radioactive isotope for several years. There are initially 8000 radioactive
isotopes that half every year. The scientist uses the expression 8000(2) *
to calculate the
number of radioactive isotopes that remain after x years. What does the (2) *
represent?
The number that the initial number of radioactive isotopes is divided by
The current number of radioactive isotopes
目 囝1
4x
The initial number of radioactive isotopes
4x
• The factor that the initial number of radioactive isotopes is multiplied by

Answer 1

"The factor that the initial number of radioactive isotopes is multiplied by."

Reason: Halving each year means you multiply by (1/2) each year, so after x years the initial 8000 is multiplied by (1/2)^x (which is the same as 2^(−x)).