The present age of Bob is equal to Abby's age $8$ years ago. Four years hence,the ratio between Bob's age and Abby's age will be $4:5$. What is Bob's present age (in years)?

$A$ shopkeeper wishes to give $5 \%$ commission on the marked price of an article but also wants to earn a profit of $10 \%$. If his cost price is $₹ 95$,then the marked price is (in $₹$):

$A$ sells a bicycle to $B$ at a profit of $20 \%.$ $B$ sells it to $C$ at a profit of $25 \%.$ If $C$ pays $Rs. 225$ for it,the cost price of the bicycle for $A$ is (in $Rs.$)

$A$ fan costing $Rs. 1200$ is being sold for $Rs. 1500$. What is the profit percent?

If a discount of $10 \%$ is given on the marked price of a radio,the gain is $20 \%$. If the discount is increased to $20 \%$,the gain is......$\%$

$A$ shopkeeper sold sarees at $Rs. 266$ each after giving a $5\%$ discount on the labelled price. Had he not given the discount,he would have earned a profit of $12\%$ on the cost price. What was the cost price of each saree? (in $Rs.$)