Question

a piece of cloth costs rs 35 . if the piece was 4 metre longer and each metre costs rs 1 less , the cost would remain unchanged . how long is the piece of cloth?

Answer 1

piece of a cloth -35
from every metre 1 rupee is less
4 metre cost = 35×4
= 140
from every metre 1 rupee is less
= 140-4
= 136.

Answer 2

SOLUTION :  

Let the length of the piece of  cloth be x metres.

Then , Rate per meter = 35/x

New length of the piece of  cloth be (x + 4)  

New Rate per meter = 35/(x + 4)

[Cost remain same ]

A.T.Q

35/x - 1 = 35/(x + 4)

35/x - 35/(x + 4) = 1

[35(x + 4) - 35x] / [x(x + 4)] = 1

[By taking LCM]  

35(x + 4) - 35x = x(x + 4)

35x + 140 - 35x = x² + 4x

x² + 4x - 35x - 35x - 140 = 0

x² + 4x - 140 = 0

x² + 14x - 10x - 140 = 0

[By middle term splitting]

x(x + 14) - 10(x + 14) = 0

(x + 14) (x - 10) = 0

(x + 14) = 0  or (x - 10) = 0

x = - 14  or x = 10

Since, length can't be negative,so x ≠ - 14

Therefore , x = 10

Hence, the length of piece of cloth is 10 m.

HOPE THIS ANSWER WILL HELP YOU….