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 $years$)
$24$
$32$
$40$
$20$
By selling an umbrella for $Rs.\, 300,$ a shopkeeper gains $20 \%$. During a clearance sale, the shopkeeper allows a discount of $10 \%$ on the marked price. His gain per cent during the sale is
By selling an article for $Rs.\, 102,$ there is a loss of $15 \%$ When the article is sold for $RS.\,134.40,$ the net result in the transaction is
A rice trader buys $8$ quintals of rice for $Rs.\, 3,600,10 \%$ rice is lost in transportation. At what rate should he sell to earn $15 \%$ profit in $Rs.$ per quintal ?
Successive discounts of $10 \%, 12 \%$ and $15 \%$ amount to a single discount of
An electric pump was sold at a profit of $15 \% .$ Had it been sold.for $Rs.\, 600$ , the profit would have been $20 \% .$ The former selling price is in $Rs.?$