# Examples for 8th grade - page 2

- Five pupils

Five pupils clean 30 chairs one hour before four pupils. How many chairs clean one pupil in 1 hour? - Sss triangle

Calculate the area and heights in the triangle ABC by sides a = 8cm, b = 11cm, c = 12cm - Linear system

Solve a set of two equations of two unknowns: 1.5x+1.2y=0.6 0.8x-0.2y=2 - Pavement

Calculate the length of the pavement that runs through a circular square with a diameter of 40 m if distance the pavement from the center is 15 m. - The cube

The cube has an edge of 12 dm. The second cube has an edge exactly 20% longer. How many % is more water in the second cube than in the first cube, if the first cube is full to 3/4 and the second to 3/8? - Exchange rates

If the Canadian dollar appreciated by C$0.005 relative to the US dollar, what would be the new value of the Canadian dollar per US dollar? Assume the current exchange rate was US$1 = C$0.907. - Tickets

On Monday, 33 tickets were sold. Every next day, twice as many as the previous day. How many tickets were sold on Friday and how many totally from Monday to Friday? - Composite ratio

Jakub, Aneta, and Lenka divided 1342 USD in the ratio 5/2: 3/10: 1/4. How much did Lenka take? - Two masters

The two masters will make as many parts as five apprentices at the same time. An eight-hour shift begins at 6 o'clock. When can a master finish the job to produce just as much as an apprentice for the whole shift? - Overtaking

On the direct road, the passenger car overtakes the slower bus by starting to overtake 20 meters from the bus and after passing it ahead of it again 20 meters away. The car overtakes at a steady speed of 72 km/h, the bus goes at a steady speed of 54 km/h.. - The swimmer

The swimmer swims at a constant speed of 0.85 m/s relative to water flow. The current speed in the river is 0.40 m/s, the river width is 90 m. a) What is the resulting speed of the swimmer with respect to the tree on the riverbank when the swimmer motion - Tickets 4

Stacey is selling tickets to the school play. The tickets are $7 for adults and $5 for children. She sells twice as many adult tickets as children's tickets and brings in a total of $342. How many of each kind of ticket did she sell? - Three brothers

The three brothers have a total of 42 years. Jan is five years younger than Peter and Peter is 2 years younger than Michael. How many years has each of them? - Supplementary angles

One of the supplementary angles is larger by 33° than the second one. Calculate the angles size. - Discount

The dress was discounted by CZK 115, which was 12% of the original price. What is the cost of the dress after the discount? - Sugars

In what ratio must two sorts of sugar, costing #390 and #315 per kg respectively, be mixed in order to produce a mixture worth #369 per kg? - Ping time

Calculate theoretical ping time between Orlando and Shenzhen which is 14102 km distant. Ping time measures the round-trip time for small messages sent from the origin to a destination that is echoed back to the source. The name comes from active sonar term - Progression

12, 60, -300,1500 need next 2 numbers of pattern - Summer tires

Three tire servants have to change the summer tires on 6 cars in 2 hours. Mark's replacement would take 4.5 hours, Jirka would do it in 3 hours and 10 minutes, and Honza in 4 hours. Will they be able to replace all tires at the desired time? - Phone plan

Victoria's cell phone plan costs $30.00 a month. If she used 12.5 hours in May, how much did Victoria pay per minute?

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