Use the following information to answer the given question
Rufai, a vulcanize bought 4 machines for N20,200 and incurred the following expenses for the year ended 31st December, 1990
\(\begin{array}{c|c} Glue & N2,100 \\ Thread & N600 \\ Kerosene & N900 \\ Rubber & N558 \\ Matched & N110\end{array}\)
He received N5,772 from customers. Two machines were later sold for N6,990 and N5,670 respectively. What is his revenue receipt?