9.A

9.A to attend more than 20 students but fewer than 40 students. A third of the pupils wrote a math test to mark 1, the sixth to mark 2, the ninth to mark 3. No one gets mark 4. How many students of class 9.A wrote a test to mark 5?

Correct result:

n =  14

Solution:

$$\begin{gathered} 3\mathrm{.}\mathrm{.}\mathrm{.}primenumber \\ 6=2\cdot 3 \\ 9=3^2 \\ LCM(3,6,9)=2\cdot 3^2=18 \\ m=LCM(3,6,9)=18 \\ 20<=t<=40 \\ t=2m \\ t=2\cdot m=2\cdot 18=36 \\ n=t\cdot (1-1\mathrm{/}3-1\mathrm{/}6-1\mathrm{/}9)=36\cdot (1-1\mathrm{/}3-1\mathrm{/}6-1\mathrm{/}9)=14 \end{gathered}$$

Try another example

Showing 0 comments:

Next similar math problems:

• Shepherd
  The shepherd has fewer than 500 sheep; where they can be up to 2, 3, 4, 5, 6 row is always 1 remain, and as can be increased up to 7 rows of the sheep, and it is not increased no ovine. How many sheep has a shepherd?
• LCD 2
  The least common denominator of 2/5, 1/2, and 3/4
• School
  Less than 500 pupils attend school. When it is sorted into pairs, one pupil remains. Similarly, when sorted into 3, 4, 5 and 6 members team one remains. Sorted to seven members teams, no left behind. How many pupils are attending this school?
• Class 9A
  On the final certificate have one quarter of the class 9A mark "C" of mathematics, seventh mark "C" from the Czech language and two students failed in chemistry. How many students attend class 9A?
• School books
  At the beginning of the school year, the teacher distributed 480 workbooks and 220 textbooks. How many pupils could have the most in the classroom?
• Four classses
  Students of all 7, 8 and 9 classes in one school may take up 4,5,6 and 7 abreast and nobody will left. How many is the average count of pupils in one class if there are always four classes each grade?
• Four poplars
  Four poplars are growing along the way. The distances between them are 35 m, 14 m, and 91 m. At least how many poplars need to be dropped to create the same spacing between the trees? How many meters will it be?
• Hectares
  The tractor plows the first day of 4.5ha, the second day 6.3ha and the third day 5.4ha. It worked whole hours a day, and its hourly performance did not change and was the highest of the possible. How many hectares did it plow in one hour (what is it perfo
• Fewer than 500 sheep,
  There are fewer than 500 sheep, but if they stand in a double, triple, quadruple, five and sixth order, one sheep will remain. But they can stand in the seventh order. How many are sheep?
• Plumber
  Plumber had to cut the metal strip with dimensions 380 cm and 60 cm to the largest squares so that no waste. Calculate the length of the sides of a square. How many squares cut it?
• MO C–I–1 2018
  An unknown number is divisible by just four numbers from the set {6, 15, 20, 21, 70}. Determine which ones.
• Apples and pears
  Mom divided 24 apples and 15 pears to children. Each child received the same number of apples and pears - same number as his siblings. How many apples (j=?) and pears (h=?) received each child?
• Blades
  1st blade 2,5 m, 2nd blade. .1.75 m. How many same long pieces of this two blades can be do the biggest? How long is one piece?
• Trees in alley
  There are four trees in the alley between which the distances are 35m, 15m and 95m. Trees must be laid in the spaces so that the distance is the same and the maximum. How many trees will they put in and what will be the distance between them?
• Three friends
  Three friends had balls in ratio 2: 7: 4 at the start of the game. Could they have the same number of balls at the end of the game? Write 0, if not, or write the minimum number of balls they had together.
• The tickets
  The tickets to the show cost some integer number greater than 1. Also, the sum of the price of the children's and adult tickets, as well as their product, was the power of the prime number. Find all possible ticket prices.
• Package
  The package has no more than 66 m of cloth. If we just cut it all on the blouses or all on dresses, no cloth left remain. On the one blouse consumes 1.3 m of cloth and on one dress 5 m. Determine the amount of the cloth in the package.