Question

A wall is of the form of a trapezium with height $4$ m and parallel sides being $3$ m and $5$ m. What is the cost of painting the wall, if the rate of painting is Rs. $25$ per square metre?

• A. Rs. $240$
• B. Rs. $400$
• C. Rs. $480$
• D. Rs. $800$

Answer 1

The correct option is B Rs. $400$

Given, height of trapezium $=3$ m, two sides length $=3$ m and $=5$ m.

Area of trapezium $=\frac{{\text{side}}_1+{\text{side}}_2}{2}\times \text{height}$

Area of wall $=\frac{1}{2}(5+3)\times 4$

$=\frac{1}{2}\times 8\times 4=16$ sq. m

The rate of painting is Rs. $25$ per square metre.
Thus cost of painting for $16$ sq. m is $=16\times 25=$ Rs. $400$.