Question

An electric cable costs RS 200. If the cable was 5 metres longer and each metre of cable costs RS 2 less, the cost of the table would have remain unchanged. Find the length of the cable.

Answer 1

Let the length of cable is X m

cost of cable =Rs ( 200/X) per mt.

(X+5)* [(200/X)-2] = 200

solving this equation we Get : X^2-5X-500 = 0

On solving this quadratic equation we get answer X =68.2548 m