Math, asked by rajathreigns, 1 year ago

the ratio of work done by (x+2) men in (x-2) days to that of (x-1) men in (x+1) days is 4:5 , the value of x is

Answers

Answered by priya5643
20
4 will be the answer
Attachments:
Answered by chaitragouda8296
5

Given :

Work done by men is ( x + 2 ) in ( x - 2 ) days &

Work done by men is ( x - 1 ) in ( x + 1 ) days is in the ratio 4 : 5

Solution :

(x + 2)(x - 2)</u><u>:</u><u>(x - 1)(x + 1) = 4</u><u>:</u><u>5 \\  \\  \frac{(x + 2)(x - 2)}{(x - 1)(x + 1)}  =  \frac{4}{5}  \\  \\ numerator \:  \: and \:  \: denominator \:  \: is \:  \: the \:  \: form \:  \: (x + y)(x - y) =  {x}^{2}  -  {y}^{2}  \\  \\   \frac{ {x}^{2} -  {2}^{2}  }{ {x}^{2}  -  {1}^{2} }  =  \frac{4}{5}  \\  \\  \frac{ {x}^{2}  - 4}{ {x}^{2}  - 1}  =  \frac{4}{5}  \\  \\ by \:  \: cross \:  \: multiplying \:  \:  \\  \\ 5 {x}^{2}  - 20 = 4 {x}^{2}  - 4 \\  \\ 5 {x}^{2}  -  {4x}^{2}  - 20 + 4 = 0 \\  \\  {x}^{2}  - 16 = 0 \\  \\  {x}^{2}  -  {4}^{2}  = 0 \\  \\ (x + 4)(x - 4) = 0 \\  \\  \\ x + 4 = 0 \\ x =  - 4 \\  \\  \\ x - 4 = 0 \\ x = 4

The value of x is 4

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