Question

ruppes 480 is divided equally among a certain number of children. If the number of children were 20 more then each other would have got rupees 12 less. Find the original number of children.​

Answer 1

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no of children=x

1 child receive money=480/x

A)Q

20more children are added

1 child receive money=489/x+20

480/x-480/x+20=12

480(x+20)-480x

____________=12

x(x+20)

480(x+20-x)

___________=12

x²+20x

480×20/12=x²+20x

40×20=x²+20x

800=x²+20x

0=x²+20x-800

0=x²+40x-20x-800

0=x(x+40)-20(x+40)

0=(x+40)(x-20)

let x+40=0 and x-20=0

x=-40 and x=20

since number of children cannot be negative

therefore no of children =20

Answer 2

no of children=x

1 child receive money=480/x

A)Q

20more children are added

1 child receive money=489/x+20

480/x-480/x+20=12

480(x+20)-480x

____________=12

x(x+20)

480(x+20-x)

___________=12

x²+20x

480×20/12=x²+20x

40×20=x²+20x

800=x²+20x

0=x²+20x-800

0=x²+40x-20x-800

0=x(x+40)-20(x+40)

0=(x+40)(x-20)

let x+40=0 and x-20=0

x=-40 and x=20

as number of children cannot be negative

thus the answer is 20 children