Apothecaries (druggists) use the following set of measures in the English system:
$$
\begin{aligned}
20 \text { grains ap } &=1 \text { scruple (exact) } \\
3 \text { scruples } &=1 \text { dram ap (exact) } \\
8 \text { dram ap } &=1 \mathrm{oz} \text { ap (exact) } \\
1 \text { dram ap } &=3.888 \mathrm{~g}
\end{aligned}
$$
a. Is an apothecary grain the same as a troy grain? (See Exercise 45.)
b. $102 \mathrm{ap}=$_____oz troy.
c. An aspirin tablet contains $5.00 \times 10^{2} \mathrm{mg}$ of active ingredient. What mass in grains ap of active ingredient does it contain? What mass in scruples?
d. What is the mass of 1 scruple in grams?