# Percentages - high school - math problems

#### Number of problems found: 250

• Demographics The population grew in the city in 10 years from 30000 to 34000. What is the average annual percentage increase of population?
• Decibel By what percentage does the sound intensity increase if the sound intensity level increases by 1 dB?
• Investment 1000\$ is invested at 10% compound interest. What factor is the capital multiplied by each year? How much will be there after n=12 years?
• Pipeline How much percent has changed (reduced) area of pipe cross-section, if circular shape changed to square with same perimeter?
• Win in raffle The raffle tickets were sold 200, 5 of which were winning. What is the probability that Peter, who bought one ticket will win?
• Three colors Find the probability that 3 balls of the same color will be drawn from fate with 10 white, 10 red, and 10 blue balls.
• Kostka Kostka je vepsána do koule o poloměru r = 6 cm. Kolik procent tvoří objem kostky z objemu koule?
• Three dice What is the probability that when we roll three dice, we roll the numbers 1,2,3?
• Ace From complete sets of playing cards (32 cards), we pulled out one card. What is the probability of pulling the ace?
• Vinegar mixing We mix 70g water and 50g 8% vinegar. How many percents of the solution of vinegar we produce?
• Medicine We test medicine on 6 patients. For all drug doesn't work. If the drug success rate of 20%, what is the probability that medicine does not work?
• The bus stop The bus stop waiting room has the shape of a regular quadrilateral pyramid 4 m high with a 5 m base edge. Calculate how many m2 roofing is required to cover the three walls of the sheathing, taking into account 40% of the additional coverage.
• Cube edges If the edge length of the cube increases by 50%, how does the volume of this cube increase?
• Sixty Sixty percent of one-fifteen of the total is equal to thirty. What are two percent of the total? On a straight stretch of road is marked 12 percent drop. What angle makes the direction of the road with the horizontal plane?
• Borrowing I borrow 25,000 to 6.9% p.a.. I pay 500 per month. How much will I pay and for how long?
• Sale If the product twice price cut by 25%, what percentage was price cut in total?
• Two aces From a 32 card box we randomly pick 1 card and then 2 more cards. What is the probability that last two drawn cards are aces?
• Deposit If you deposit 719 euros the beginning of each year, how much money we have at 1.3% (compound) interest after 9 years?
• An investment How long will it take for an investment to double at a simple interest rate of 5.10% p. A. ? Express the answer in years and months, rounded up to the next month.

Do you have an interesting mathematical word problem that you can't solve it? Submit a math problem, and we can try to solve it.

We will send a solution to your e-mail address. Solved examples are also published here. Please enter the e-mail correctly and check whether you don't have a full mailbox.

Please do not submit problems from current active competitions such as Mathematical Olympiad, correspondence seminars etc...