I believe the answer is A. However, I would double check the formula.
The mass decay rate is of the form

where
m₀ = 3000 g,the initial mass
k = the decay constant
t = time, years.
Because the half-life is 30 years, therefore

After 60 years, the mass remaining is

Answer: 750 g
Answer:
Although atoms are the smallest units that can be found in all matter, these atoms have a complex structure when experimentally analyzed. In order to understand almost all concepts in chemistry, it is essential to clearly understand the basic structure of an atom. Crystals are solid compounds made out of a number of atoms or molecules. There are particular arrangements in crystals. These arrangements are called crystal structures. Examining the crystal structure is very important in determine
Explanation:
Acid palmitic acid has higher melting point, because it has two more methylene groups.

Acid palmitic acid has higher melting point, because it has two more methylene groups.
Giving it a greater surface area and therefore more intermolecular van der waals interact than the myristic acid.
stearic arid 
linoleic acid
(two double bond)
Stearic acid has higher Melting point, because it does not have any Carbon-Carbon double bonds, whereas linoleic acid has two cis double bonds which prevent the molecules from packing closely together.
Oleic Acid and Linoleic acid.
-one double bond (cis)
Acid palmitic acid has higher melting point, because it has two more methylene groups.
For more such question on methylene group.
brainly.com/question/4279223
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An independent variable is the variable you are changing in order to measure the dependent variable, which is what you are measuring.
In this example, the
independent variable: chemicals in solution
dependent variable: temperature of solution