volume = l x w x h
volume = 20 x 35 x 50 = 35,000 cubic cm
1 cubic cm = 0.001 liter
35000 x 0.001 = 35 liters of water is needed
The half life of a decaying substance is defined as the time at which the substance decreases to one-half of its original value. In this case, given hlf-life of 10 years and an original mass of 50 grams, after 10 years, the isotope mass becomes 50*0.5 or 25 grams. Answer is B.
