Question

A piece of iron rod costs Rs. 60. If the rod was 2 meters shorter and
each meter costs Re. 1.00 more, the cost would remain unchanged,
What is the length of the rod?
what is the answer​

Answer 1

Answer:

12m

Explanation:

Let L denotes the length in meter of the given iron rod that costs Rs 60. So the cost per meter of this iron rod = 60/L.

It is given that If the rod was 2 meters shorter and each meter costs Rs. 1.00 more, the cost would remain unchanged. So we get the following equation,

(L - 2)*(60/L + 1) = 60 or L*(60/L) + L - 2*(60/L) - 2 = 60 or L - 120/L - 2 = 0

or L^2 - 2L - 120 = 0 or (L - 12)(L + 10) = 0

Hence, as because L>0 therefore we have L = 12 (meters) [Ans]