# Examples for 9th grade - page 35

- Pipeline

How much percent has changed (reduced) area of pipe cross-section, if circular shape changed to square with same perimeter? - Ray

Light ray loses 1/19 of brightness passing through glass plate. What is the brightness of the ray after passing through 7 identical plates? - Cosine

Calculate the cosine of the smallest internal angle in a right-angled triangle with cathetus 3 and 8 and with the hypotenuse 8.544. - Scale

Cylinder was drawn in scale 2:1. How many times is the volume of the cylinder smaller in reality? - Peleton

Cycling race was run at an average speed of 45 km/h. One cyclist lost with defect 8 minutes. How long and how far he must go at speed 51 km/h to catch peleton again? - Aluminum wire

Aluminum wire of 3 mm diameter has a total weight of 1909 kg and a density of 2700 kg/m^{3.}How long is the wire bundle? - Pedestrian and the cyclist

Pedestrian and cyclist went against each from the two cities that are distant 40 km. Pedestrian started 30 minutes before the cyclist and walk an average speed of 5 km/h. What speed went cyclist when met after 120 minutes from the start of the pedestrian? - ICE train

German runways test a new ICE train between Munich and Berlin. The train runs to Berlin at a slow speed of 100 km/h. Back from Berlin goes faster. How quickly did the train have to go on a return trip so that the total average train speed for both journeys - Cable car

Cable car rises at an angle 45° and connects the upper and lower station with an altitude difference of 744 m. How long is "endless" tow rope? - Sports games

Pupils of same school participated district sports games. When dividing into teams found that in the case of the creation teams with 4 pupils remaining 1 pupil, in the case of a five-member teams remaining 2 pupils and in the case of six-members teams r - Disinfecting solution

How much distilled water is necessary to pour into 500 ml of 33% hydrogen peroxide solution to obtain 3% disinfecting solution? - Function

For linear function f(x) = ax + b is f(14)=179; f(15)=154. Calculate m, if f(m) = 2019 . - Triangular pyramid

Determine the volume and surface area of a regular triangular pyramid having a base edge a=20 cm and a lateral edge b = 35 cm - Euclid 5

Calculate the length of remain sides of a right triangle ABC if a = 7 cm and height v_{c}= 5 cm. - Train 2

The train slowed down from 90 km/h to 72 km/h in 5 seconds. How long track travel? - Tickets

Tickets to the zoo cost $4 for children, $5 for teenagers and $6 for adults. In the high season, 1200 people come to the zoo every day. On a certain day, the total revenue at the zoo was $5300. For every 3 teenagers, 8 children went to the zoo. How man - Tin with oil

Tin with oil has the shape of a rotating cylinder whose height is equal to the diameter of its base. Canned surface is 1884 cm^{2.}Calculate how many liters of oil is in the tin. - Car rent

Rental cars are paid a fixed daily fee plus 16 cents for each kilometer traveled. Samuel want to rent a car for a day and worked out that will pay 175 euros. When paying he got a 20% discount on the daily fee, the cost per kilometer is unchanged. Samuel th - Father and son

Father is 48 years old, son 23. When will be the father twice older than a son? - Clock hands

The hands on the clock shows the time 12 hours and 2 minutes. Calculate the size of a sharp angle between clock hands three hours later.

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