# Fractions + expression of a variable from the formula - math problems

#### Number of problems found: 53

• Find unknown 2
Find unknown denominator: 2/3 -5/? = 1/4
• Simple equation 3
24 = n • 27, solve for n
• Two thirds
Find two-thirds of the number equal to two-thirds of 99
• Marriage sttus
In our city, there are 3/5 of the women married to 2/3 of the men. Find what part of the population is free.
• Unknown mixed number
Find the number that is smaller than 5 5/12 by as much as 2 2/13 is smaller than 6 1/6
• Orchard
3/5 of the trees in the orchard are apples, 1/3 are cherries and the remaining five trees are pear. How many trees are in the orchard?
• Boys and girls
There are 28 girls in the hall. 5/7 of all children are boys. How many children and how many boys are there?
How many times does the surface of a sphere decrease if we reduce its radius twice?
• Above Earth
To what height must a boy be raised above the earth in order to see one-fifth of its surface.
• Interior angles
Calculate the interior angles of a triangle that are in the ratio 2: 3: 4.
• Family
Son is 3/5 smaller than the mother. Mother is 99 cm higher than the son. How tall is the mother?
• Unknown number 5
Daniel think an integer. When he change this number at a ratio of 2:5 he got number 2.8. Determine what number think Daniel.
• Ratio of volumes
If the heights of two cylindrical drums are in the ratio 7:8 and their base radii are in the ratio 4:3. What is the ratio of their volumes?
• The tank
The tank is full up to 4/5 of the total height and contains 240 hl of water. The area of the base is 6 square meters. What is the height of the tank?
• The angles ratio
The angles in the ABC triangle are in the ratio 1: 2: 3. find the sizes of the angles and determine what kind of a triangle it is.
• Library
New books were purchased for the library. Five-eighths were professional books, one-fifth were encyclopedias, and 231 books were dictionaries. How many professional books were there?
• Oranges
Mother divided her three children's oranges in a ratio of 6:5:4. Two children gave 45 oranges. How many oranges were there?
• The pole
The telegraph pole is supported by a 4 m bullet at 3/4 of its height, the end of which is at a distance 2.5 m from the pole post. Calculate the height of the telegraph pole.
• Hectoliters of water
There are 942 hectoliters of water in a cylindrical tank with an inner diameter of 6 m. The water reaches two thirds of the depth of the tank. Calculate its depth.
• Twelve
Twelve students work on a week forestry brigade. One hundred spruces will receive x CZK, one hundred pine y CZK. How many receive each one students did in one day if they planted a total of 25,000 spruces per week and 30,000 pine trees? Express by express

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