Question

5. if X+Y=20 and X-Y=4 then the
*
values of X and Y are:
O (a) X=8, Y=12
O (b) X=8, Y=8
O (c) X=12, Y=12
O
(d) X=12, Y=8​

Answer 1

Answer:

option D

As adding eq1 and 2

it will be

2X = 24

=> X = 12

and putting value in eq1

12 + Y = 20

=> Y = 20 - 12

=> Y = 8

Hence your answer is option D

Answer 2

$\large\sf\underline{✰\:Given}$

• $\sf\:x+y=20-------(i)$

• $\sf\:x-y=4-------(ii)$

$\large\sf\underline{✰\:To\:find}$

• $\sf\:Value\:of\:x\:and\:y$

$\large\sf\underline{✰\:Solution}$

Let's take the equation (i)

$\sf⟹\:x+y=20$

$\sf⟹\:x=20-y$

Now substituting the value of x in equation (ii)

$\sf⟹\:x-y=4$

$\sf⟹\:20-y-y=4$

$\sf⟹\:20-2y=4$

$\sf⟹\:-2y=4-20$

$\sf⟹\:-2y=-16$

$\sf⟹\:2y=16["-"\:and\:"-"\:cancelled]$

$\sf⟹\:y=\frac{16}{2}$

$\tt\pink{➪\:y=8}$

Now again substituting the value of y in (i)

$\sf⟹\:x+y=20$

$\sf⟹\:x+8=20$

$\sf\:x=20-8$

$\tt\pink{➪\:x=12 }$

$\tt\red{∴\:Option\:(D) \:is\:correct}$

Thnku ❣