$3.$ A rectangular area $10$ miles in north$-$south direction by $40$ miles in east$-$west direction is to be covered with aerial photography having a scale of $1$:$6000.$ End lap and side lap are to be $60\%$ and $30\%$ respectively. A camera having a $23$ cm square format is to be used. Compute the total number of photographs in the project, assuming that the flight strips are flown in an east$-$west direction, and that the coverage of the first and last flight lines are $75\%$ within the project boundary. Also, add $2$ photos at the end of each strip to ensure complete coverage.