Question

A canal of width 1 m is constructed all along inside the field which is 24 m long and 15 m wide. Find 

(i) the area of the canal 

(ii) the cost of constructing the canal at the rate of Rs 12 per sq.m.

Answer 1

Length of the field L = 24 m

Width (Breadth) of the field B = 15 m

(i) Area of the field = L x B sq. units 

= 24 x 15 m² 

= 360 m²

(ii) Width of the canal (W) = 1 m

Length of the field without canal (l) 

= L – 2(W) 

= 24 – 2(1) m

= 24 – 2 m 

= 22 m

Width of the field without canal (b) = B – 2W 

= 15 – 2(1) m

= 15 – 2 m 

= 13 m

Area of the field without canal = l x b sq. units 

= 22 x 13 m² 

= 286 m²

Area of the canal = (360 – 286)m² = 74 m²

Cost of constructing 1 m² canal = Rs 12

Cost of the constructing 74 m² canal = Rs 12 x 74 = Rs 888