# Examples for 9th grade - page 10

- Percent chaining

Calculate 20% from 70% from 80 km - Solutions

How much 60% solution and how much 35% solution is needed to create 100 l of 40% solution? - Digging companies

Company A would dig a pit for 12 days, company B for 15 days, company C for 20 days and the company D for 24 days. Work began together companies C and D, but after three days joined them other two companies. How long took to dig a pit? - Spherical cap

From the sphere of radius 12 was truncated spherical cap. Its height is 4. What part of the volume is spherical cap from whole sphere? - Pediatrician

Pediatrician this month of 21 working days takes 3 days holidays. What is the probability that on Monday will be at work? - Sales off

If a sweater sells for $ 12 after a 25% markdown, what was its original price? - Prism

The lenght, width and height of a right prism are 18, 14 and 9 respectively. What is the lenght of the longest segment whose endpoints are vertices of the prism? - Compass

What angle are between directions W (West) and SE (SouthEast) on the compass? - Oil rig

Oil drilling rig is 23 meters height and fix the ropes which ends are 8 meters away from the foot of the tower. How long are these ropes? - Cosine

The point (21, 20) is on the terminal side of angle θ. cos θ = ? - Components

In the box are 6 white, 4 blue and 2 red components. What is the probability that we pull one white, one blue and one red component without returning? - Metals

In the Hockey World Cup play eight teams, determine how many ways can they win gold, silver and bronze medals. - 4 pipes

The tank flows out by 4 pipes in 6 hours 120 hl water. How much water flows out of 5 pipes of the same diameter in 14 hours? - Cars plates

How many different licence plates can country have, given that they use 3 letters followed by 4 digits? - Discount

Product has been discounted twice by 14%. What is the total discount given? - Cylinder - A&V

The cylinder has a volume 253. The base has a radius 5. What is the area of surface of the cylinder? - Family

Family has 4 children. Ondra is 3 years older than Matthew and Karlos 5 years older than the youngest Jane. We know that they are together 30 years and 3 years ago they were together 19 years. Determine how old the children are. - Euclid 5

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

On the racing track circling three cars. The first passes one circuit for 8 seconds, the second for 16 seconds and a third for 15 seconds. a) Calculate number of seconds since the start to catch all three cars together for the first time again across the. - Spherical segment

Spherical segment with height h=8 has a volume V=294. Calculate the radius of the sphere of which is cut this segment.

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