(d) Let CP of the cow be ₹ x and that of buffalo be ₹ y
∴ SP of cow at loss of 10% = (x - 10% of x)
=
(x−×x) = ₹
Also, SP of buffalo at profit of 20% = (y +20% of y)
=
(y+×y) = ₹
According to the question,
+ = (x + y)
⇒
= x + y
⇒
9x + 12y = 10x + 10y
⇒
x = 2y
......(i)
Now, SP of cow at 5% profit = (x + 5% of x)
=
(x+×x) =
(x+)=₹Also, SP of buffalo at 15% loss = (y - 5% of x)
=
(y−×y) =
According to the question,
(x+ y ) -
(+) = 800
⇒20x + 20y - 21x - 17y = 800 x 20
⇒
-x + 3y = 16000
.........(ii)
⇒ -2 y + 3 y = 16000 [From Eq. (i)]
y = 16000
So, the required selling price of buffalo is ₹ 16000.