Question

Inside a rectangular ground 50m by 40m run two crossing pathways each 4m broad and at right angle to the length and breadth of the ground find the cost of repairing the pathways of rs.30 per sq.m

Answer 1

1. A rectangular grassy lawn measuring 40 m by 25 m is to be surrounded externally by a path which is 2 m wide. Calculate the cost of leveling the path at the rate of Rs 8.25 per square meter.

Solution:

RD Sharma Solutions for Class 7 Maths Chapter 20 Mensuration - I (Perimeter and Area of Rectilinear Figures) Image 3

Let PQRS be the rectangular grassy lawn and let length = AB and breadth = BC

Given Length AB = 40 m and breadth BC = 25 m

Area of lawn PQRS = 40 m x 25 m = 1000 m2

Length AB = (40 + 2 + 2) m = 44 m

Breadth BC = (25 + 2 + 2) m = 29 m

Area of ABCD = 44 m x 29 m = 1276 m2

Now, Area of the path = Area of ABCD – Area of the lawn PQRS

= 1276 m2 – 1000 m2  

= 276 m2

Rate of levelling the path = Rs. 8.25 per m2

Cost of levelling the path = (8.25 x 276)

= Rs. 2277