Percentage and Profit & Loss

69% of the students of a certain class took Mathematics and 47% took Biology. If each student took Biology or Mathematics and 44 took both, what is the total number of students in the class?

The value of a machine is Tk. 6,250. Its value decreases by 10% during the first year, 20% during second year and 30% during the third year. What will be the value of the machine after 3 years?

There are n students in a school. If r% among the students are 12 years or younger, which of the following expressions represents the number of students who are older than 12?

An employer pays 3 workers X, Y and Z a total of Tk. 36,600 a week. X is paid 125% of the amount Y is paid and 80% of the amount Z is paid. How much does X make a week?

A sells an article which costs him Tk. 400 to B at a profit of 20%. B then sells it to C, making a profit of 10% on the price he paid to A. How much dose C pay to B?

If 18 is 15% of 50% of a certain number, what is the number? 

The length and breadth of a square are increased by 40% and 30% respectively. The area of the resulting rectangle exceeds the area of the square by:

A lamp is manufactured to sell for $ 35.00, which yields a profit of 25% of cost. If the profit is to be reduced to 15% of the cost, what will be the new retail price of the lamp?

A shopkeeper purchases 15 mangoes for Tk. 10 and sells them at 10 mangoes for Tk. 15. Thus, he earns a profit of ___ .

Salma's average in four tests is 80%. What mark does she need to score in her fifth test to make her average 84%? 

What number divided by 50 gives 3.6%?

On Dhaka- Sylhet highway 5% of the drivers are fined for exceeding the speed limit. However, 80% of the drivers who exceed the speed limit are not fined. What percentage of drivers on this highway exceed the speed limit?

If the price of an item is increased by 10% and then decreased by 10% , the net effect on the price of the item is -

A man purchases two clocks A and B at a total cost of Tk. 650. He sells A with a 20% profit and B at a loss of 25% and gets the same selling price for both clocks. What are the purchasing prices of A and B respectively?

If the price of gasoline increases by 25% and Ron intends to spend only 15% more on gasoline, by how much % should he reduce the quantity of gasoline that he buys?

A school has only four classes having 10, 20, 30 and 40 students respectively with pass percentage of 20%, 30%, 60% and 100% respectively. Find the pass percentage of the entire school. 

Rahim invested in all Tk. 2,600 in three different schemes at 8%, 4% and 6% per annum simple interest. At the end of the year, he received the same interest in all the three schemes. What is the money invested in scheme having 4% rate of interest?

Out of 7,500 applications for a recruitment test, 1,500 failed to appear for the test. What percent of the total applicants did appear for the test?

A milkman purchases the milk at Tk. x per liter and sells it a Tk. 2x per liter still he mixes 2 Iiters water with every 6 liters of pure milk. What is the profit percentage?

The price of raw materials has gone up by 15%, labor cost has also increased from 25% of the cost of raw material to 30% of the cost of raw material. By how much percentage should there be reduction in the usage of raw materials so as to keep the cost same?