Present age of Bob is equal to Abby's age $8\, years$ ago. Four years hence, the respective ratio between Bob's age and Abby's age will be $4: 5$ at that time. What is Bob's present age? (in $years$)
$24$
$32$
$40$
$20$
If eggs are bought $12$ for $Rs.\, 10$ and sold at $10$ for $Rs.\, 12$. What is the gain or loss $\%.$
Sardar singh bought $200$ dozen oranges at $Rs.\,10$ a dozen. He spent ₹500 on transportation. He sold them at $Rs.\,1$ each. What was his profit or loss percent?
If $11$ Mango are bought for $Rs.\, 10$ and sold at $10$ for $Rs.\, 11 .$ What was Gain or Loss $\% ?$
A reduction of $10 \%$ in the price of rice enables to obtain $25\, kg$ more for $Rs.$ $2250 .$ Find the reduced price per $kg$ of the rice. (in $Rs.$)
A man sold two cows at $Rs. \,1995$ each. On one he lost $10 \%$ and on the other he gained $10 \% .$ What his gain or loss percent?