Question

A sheet is in the form of a rhombus whose diagonals are 10 m and 8 m. The cost of painting both of its surfaces at the rate of Rs 70 per m² is 

(a) Rs 5600 

(b) Rs 4000 

(c) Rs 2800 

(d) Rs 2000

Answer 1

(a) Rs 5600.

Cost of painting both its surfaces 

= 2 × 70 × Area of one surface

= Rs \(\bigg(2\times70\times\frac12\times10\times8\bigg)\) = Rs 5600.