# Examples for 7th grade (seventh) - page 53

- Octagonal mat

Octagonal mat formed from a square plate with a side of 40 cm so that every corner cut the isosceles triangle with leg 3.6 cm. What is the content area of one mat? - Two rulers

We have two rulers. Scale interval on first rulers are a spaced 1 cm and on second spaced 15 mm. Rulers are attached to each other so that they match initial divider commas. What next dividers commas coincide? Find at least three cases. - Pulley

On wheels with a diameter of 40 cm is fixed rope with the load. Calculate how far is load lifted when the wheel turns 7 times? - Concrete pipe

How much will cost cover a 6 m long concrete pipe with an outer radius 1.5 m and inner radius 0.8 meters if 1 m^{2}paint costs 24 €. - Internal angles

One internal angle of the triangle JAR is 25 degrees. The difference is the size of the two other is 15°. Identify the size of these angles. - Store

Peter paid in store 3 euros more than half the amount that was on arrival to the store. When he leave shop he left 10 euros. How many euros he had upon arrival to the store? - Bridge piers

One quarter of the bridge pier is sunk into the ground. Two thirds are in the water. Protruding above the water is 1.20 m long. Determine the height of bridge piers. - Ratios

Divide: a) 250 CZK in the ratio 2:3 b) 1000 CZK in the ratio 4:7:9 - Chicks

How many chicks were hatched from 4500 eggs, when an average of 100 eggs hatched 87 chicks? - Divisibility by 12

Replace the letters A and B by digits so that the resulting number x is divisible by twelve /find all options/. x = 2A3B How many are the overall solutions? - Three digits number 2

Find the number of all three-digit positive integers that can be put together from digits 1,2,3,4 and which are subject to the same time has the following conditions: on one positions is one of the numbers 1,3,4, on the place of hundreds 4 or 2. - Bicycle wheel

Bicycle wheel diameter is 62 cm. How many times turns the bicycle on the road 1 km long? - Ornamental shrubs

Children committed to plant 240 ornamental shrubs. Their commitment however exceeded by 48 shrubs. Write ratio of actually planted shrubs and commitment by lowest possible integers a/b. - Trees

3/5 trees are apples, cherries are 1/3. 5 trees are pear. How many is the total number of trees? - Pumps A and B

Pump A fill the tank for 12 minutes, pump B for 24 minutes. How long will take to fill the tank if he is only three minutes works A and then both pumps A and B? - One-third

A one-third of unknown number is equal to five times as great as the difference of the same unknown number and number 28. Determine the unknown number. - Sidewalk

The city park is a circular bed of flowers with a diameter of 8 meters, around it the whole length is 1 meter wide sidewalk . What is the sidewalk area? - Expressions

Expression (3a-7).(3a+7) is identical with: ? - Cylinder twice

If the radius of the cylinder increases twice, and the height is reduced twice, then the volume of the cylinder increases (how many times?): - Jam

Jar with jam weighs 800 grams. Jam weighs three times as much as the empty glass. What is the weight of jam that is in the glass?

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