From November to December of $2015,$ the price per share of

BP Oil dropped from $$99\mathrm{.}25$ to $$72\mathrm{.}25.$ Exxon shares also

dropped from $$94\mathrm{.}75$ to $$82\mathrm{.}25.$

In November, your rich cousin invested $$102,115\mathrm{.}75$ into a

combination of BP and Exxon shares. By December they sold

their shares for $$80,814\mathrm{.}75$ losing $$21,301$ from their

investment.

How many of each stock did they purchase?

They purchased

BP shares and

Exxon shares.