A farmer sold a calf and a cow for Rs. $760$ Thereby making a profit of $25\%$ on the calf and $10\%$ on the cow. By selling them for Rs. $767.5$ he would have raised a profit of $10\%$ on the calf and $25\%$ on the cow. Find the cost of each.
I tried the following:
Let the price of a calf be $x$
Let the price of a cow be $y$
$x$$+$$y$$=$Rs$760$ $[\cdots (1)]$
Profit on Rs $x$$=$$x$$/$$4$
Profit on Rs $y$$=$$y$$/$$10$
Therefore, Total profit$=$$5$$x$$+$$2$$y$/$20$
I do not know what to do next.
Let $x$ be the original cost (to the farmer) of a calf.
Let $y$ be the original cost (to the farmer) of a cow.
Then $$x + \frac x4 + y + \frac y{10} = 760 \iff \frac{5x}{4} + \frac{11y}{10} = 760\tag{1}$$
And $$x + \frac x{10} + y + \frac y4 = 767.5\iff \frac{11x}{10} + \frac{5y}{4} = 767.5\tag{2}$$
Now you can solve for $x, y$ to obtain the original cost of a calf and a cow.
If it helps you, multiplying each side of each equation by $20$ will get rid of fractions and decimals: $$25x + 22y = 15200\tag{1}$$ $$22x + 25y = 15350\tag{2}$$