A piece of cloth costs Rs. 35. If the piece were 4 m longer and each m...
Let, length of the piece of cloth = x m
Cost of cloth = Rs. 35
∴ Cost of 1 m cloth = Rs. 35/x
According to the question,
⇒ (x + 4) (35/x - 1) = 35
⇒ 35 - x + 140/x - 4 = 35
⇒ 35x - x2 + 140 - 4x = 35x
⇒ x2 + 4x - 140 = 0
⇒ x2 + 14x - 10x - 140 = 0
⇒ x(x + 14) - 10(x + 14) = 0
⇒ (x + 14) (x - 10) = 0
⇒ x = - 14 or 10
∴ The piece of cloth is 10 m long
Alternate Method:
We can tabulate the given data according to the following table:As the total remains constant at Rs.35, we get:
xy = 35
⇒ x = 35/y ----(i)
Also, (x – 1) × (y + 4) = 35 ----(ii)
On substituting the value of x from equation (i) into equation (ii), we get:
[(35/y) – 1] × (y + 4) = 35
On solving, we get:
y = -14 and 10
∴ The piece of cloth is 10 m long