A rectangular lawn is 16m×40m and has two roads each 5m wide running in the middle of it one parallel to its length and other to breadth . find the cost of constructing the roads at the rate of =80 rupees per square metre

Answer 1

one is 16 * 5
the other is (40 - 5) = 35 *5
so
80 *5 [ 16+35 ] = 80*5*51-