A tank is 25m long 12m wide and 6m deep. The cost of plastering its walls and bottom at 55 paise per sq m is	Choose one.
A) rs . 209.20 B) rs . 309.20 C) rs . 409.20 D) rs . 509.20 E) none of these

Rationale: explanation : area to be plastered = [ 2 ( l + b ) ã — h ] + ( l ã — b ) = [ 2 ( 25 + 12 ) ã — 6 ] + ( 25 ã — 12 ) = 744 sq m cost of plastering = 744 ã — ( 55 / 100 ) = rs . 409.20 answer : c
Answer: C