In a market with 100 traders, 70 sell Gari, 10 sell only Rice, and 15 sell only Maize. If n(G intersect R) is given, find the number of traders selling Gari and Rice, and possibly other goods.

Let $G$ be the set of traders who sell Gari, $R$ be the set of traders who sell Rice, and $M$ be the set of traders who sell Maize.

Given information:

• Total number of traders, $n(U) = 100$.
• Number of traders who sell Gari, $n(G) = 70$.
• Number of traders who sell only Rice, $n(R \text{ only}) = 10$.
• Number of traders who sell only Maize, $n(M \text{ only}) = 15$.
• Number of traders who sell both Gari and Rice, $n(G \cap R)