Answer:
35 years
Explanation:
We have been given an exponential decay function that models the weight of the bones of an extinct dinosaur;

The initial weight of the bones is;
substitute x with 0 in the function, f(0) = 10 grams
We are required to determine the number of years it will take for the bones to be less than 5 grams. The solution can be achieved either analytically or graphically. I obtained the graph of the function from desmos graphing tool as shown in the attachment below.
From the graph, the bones will weigh 5 grams after approximately 34.65 years. This implies that it will take 35 years for the bones to be less than 5 grams.