How many half-lives would it take for only 25% of the original radioactive isotope to remain? O 1 1 half-life O 2 half-lives 3 half-lives O 4 half-lives​

answer; the correct answer is technician a; ///100%good luck

answer: 2×10^-2kg

explanation: density= mass per volume

vol=mass/density

converting to s.i units we have;

3÷1000kg = 0.003

1.5÷100m = 0.15

0.003/0.15 = 0.02kg