the answer should be 49mm
28*7 / 4 = 49
4 divided by 6 times 5 equals 3.333
<span>As the age of the U-235 sample is 2.631 billion years, and the half-life of U-235 is 713 million years, the sample has undergone 2.361 X 1,000,000,000 / 713 X 1,000,000 = 3.69 half lives. In each half-life the sample reduces to half its original weight according to the radioactive Half-Life Formula:
ln (Nt /N0) = -kt, where N0 = mass of the original weight of radioactive material, Nt = mass of radioactive material at time t, k = decay constant and t = time interval . We have to put Nt/N0 = 1/2 for time interval = half-life.</span>
DEFINITION of 'Constant Ratio Plan' Aconstant ratio plan is a strategic asset allocation strategy, or formula, which keeps the aggressive and conservative portions of a portfolio set at a fixedratio.