# Percentages Problems

#### Number of problems found: 733

• Fish population
The number of fish in a lake decreased by 10% during period of one year. Last year there were 500 fish in the lake. What is the fish population this year?
• Tape
Video is 153% more expensive than tape recorder. How many percent is tape recorder less expensive than video?
• Crystal
The crystal grows every month 1.2 permille of its mass. For how many months to grow a crystal from weight 177 g to 384 g?
• Component fail
There is a 90 percent chance that a particular type of component will perform adequately under high temperature conditions. If the device involved has four such components, determine the probability that the device is inoperable because exactly one of the
• Container
First day got off 1/4 water from full container, second day 1/5 of the remaining water. How many percent remain container filled?
• Work
Workers works 5 days a week and has 28 days of vacation a year. Calculate how many days is out of work and express it as a percentage. Consider that a year has 52 weeks.
• Family
What is the probability that a family with 7 childrens have: exactly 6 dívek? 2 dívky and 5 boys? Consider the birth probability of a girl is 48.87% and boy 51.13%.
• Cutting circles
From the square 1 m side we have to cut the circles with a radius of 10 cm. How many discs we cut and how many percent will be waste?
• Wire
One pull of wire is reduced its diameter by 14%. What will be the diameter of wire with diameter 19 mm over 10 pulls?
• Rectangle
The width of the rectangle is 65% of its length. Perimeter of the rectangle is 132 cm. Determine the dimensions of the rectangle.
• Fruit tea
Tea contains 7% of fruit components and 12% of sugar in this component. How many percents of sugar is represented in the whole tea?
• Volume and body diagonal
Calculate how much the volume and body diagonal of the cuboid decrease if we reduce each of its three edges a, b, c by 18%?
• The crime
The crime rate of a certain city is increasing by exactly 7% each year. If there were 600 crimes in the year 1990 and the crime rate remains constant each year, determine the approximate number of crimes in the year 2025.
• Tare
Gross weight of shipment is 6927 kg and its tare is 7%. Calculate the net weight of the shipment.
• Unknown number 7
16% of the unknown number is by 21 less than unknown number itself. Determine the natural unknown number.
• Loan
If you take a bank loan \$ 10000 and we want to repay after the year, we have to pay the total amount \$ 10320/ What is the annual interest rate on this loan?
• Cube zoom
How many percents do we increase the volume and surface of the cube if we magnify its edge by 38 %?
• Rectangle
Find the dimensions of the rectangle, whose perimeter is 108 cm and the length is 25% larger than the width.
• Class
In 7.C clss are 10 girls and 20 boys. Yesterday was missing 20% of girls and 50% boys. What percentage of students missing?
• Throw
We throw 2 times with 2 dices. What is the probability that the first roll will fall more than sum of 9 and the second throw have sum 3 or does not have the sum 4?

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