Question

Two tables with top faces as two congruent trapeziums are joined as shown. The lengths of the parallel sides are $100cmand80cm$ and the height is $45cm$. Find the combined table top area and the cost of polishing it at the rate of $Rs.350$ per $m^2$.

• A. $8110c{m}^2,Rs.238.5$
• B. $8100c{m}^2,Rs.228.5$
• C. $8100c{m}^2,Rs.233.5$
• D. $8100c{m}^2,Rs.283.5$

Answer 1

The correct option is D $8100c{m}^2,Rs.283.5$

Combined area $=2$ $\times$ area of $1$ table top

$=$ $2\times \frac{1}{2}\times \left(\text{sum of parallel sides}\right)\times h$

$=$ $(100+80)\times 45=8100{cm}^3=0.81m^2$

Cost of polishing $=$ $Rs.(0.81\times 350)=Rs.283.50$