Question

pls do help I will mark as the brilliant list for the first person

Answer 1

Answer:

The rest questions are following the same pattern...So, just try to do how I did

Step-by-step explanation:

6. Let the ten's digit number = x

  Let the one's digit number = y

   According to the question:-

So,

xy = 18

=> x = 18/y

So,

10(x)+y = 10(y)+x +63

=> 10(18/y)+y = 10(y) + 18/y + 63

=> 180/y +y   = 10y + 18/y +63

=> 180/y - 18/y = 10y - y + 63

=>  162/y = 9y + 63

=>  162 = 9y^2 + 63y

=> 0 = 9y^2 + 63y -162

=> 0 =  9(y^2 +7y - 18)

=> 0 = y^2 +7y -18

=> 0 = y^2 +9y -2y -18

=> 0 = y(y+9)-2 (y+9)

=> 0 = (y-2)(y+9)

So, values of y = 2 and -9

If y = 2 then,

xy = 18 = 2x = 18 = 9

So, x = 9

So, we know that we took x in ten's place so,

The original number = 10(x)+y = 10(9)+2 = 92

7. Let the no. of books = x

Let the cost of each book = y

Cost of x books = Rs.1760

According to the question:-

Cost of x+7 = Rs.1760

Cost of each  book = y-22

so,

(x+4)(y-22) = Rs.1760

and

xy = 1760

y= 1760/x

Hence,

xy -22x +4y - 88 = Rs .1760

1760 - 22x +4(1760/x) -88 = 1760

=> -22x +4(1760/x )= 88

=> -22x + 7040/x = 88

=>  22(-x +320/x) = 88

=> 320/x -x = 4

=> 320 = (4+x )x

=> 0 = x^2 +4x -320

⇒ x² + 20x - 16x - 320 = 0

⇒ x(x + 20) - 16(x + 20) = 0

⇒ (x + 20) (x - 16) = 0

⇒ x + 20 = 0 or x - 16 = 0

⇒ x = - 20, 16 (As x can't be negative)

⇒ x = 16

Hence, the bookseller bought 16 books.

Pls mark Brainliest!!!