Examples for 9th grade - page 80

Water temperatures
To 25 liters of water at 50 °C we add 15 liters of water at a different temperature. How many °C should the water be colder than 50 °C so that 40 liters of the water obtained has a temperature 42.5 °C?
Tank diameter
A cylindrical tank has a volume of 60 hectoliters and is 2.5 meters deep. Calculate the tank diameter.
Sum of money
On a certain sum of money, invested at the rate of 10% compounded annually, the difference between the interests of the first year and the third year is 315 . Find the sum.
Factory and divisions
The factory consists of three auxiliary divisions total 2,406 employees. The second division has 76 employees less than 1st division and 3rd division has 212 employees more than the 2nd. How many employees has each division?
Dividends
The three friends divided the win by the invested money. Karlos got three eighths John 320 permille and the rest got Martin. Who got the most and which the least?
Cone
Calculate the volume of the rotating cone with a base radius 26.3 cm and a side 38.4 cm long.
Empty canister
The canister is filled with oil weight 17 kg. If filled only half weight 9 kg. What weight does my empty canister have?
Blackberries
Daniel, Jolana and Stano collected together 34 blackberries. Daniel collected 8 blackberries more than Jolana, Jolana 4 more than Stano. Determine the number blackberries each collected .
Sphere radius
The surface of the sphere is 60 cm square. Calculate its radius; result round to tenth of cm.
Enterprise company
30% of all employees in the enterprise are women. Men are 360 more. How many employees are in the company?
Holidays - on pool
Children's tickets to the swimming pool stands x € for an adult is € 2 more expensive. There was m children in the swimming pool and adults three times less. How many euros make treasurer for pool entry?
Sales off
shoes cost x euros. First they are discounted by 50%, and then 25% of the new amount. Determine what percentage of the total cost is cheaper.
Acres
Two hours 24 students harvested chestnuts on 36 acres. How many square meters harvested one student per hour?
RT perimeter
The leg of the rectangular triangle is 7 cm shorter than the second leg and 8 cm shorter than the hypotenuse. Calculate the triangle circumference.
Trapezoid - central median
The central median divides the trapezoid into two smaller trapezoids. Determines the ratio of their contents.
Prize
How many ways can be rewarded 9 participants with the first, second and third prize in a sports competition?
Fifth member
Determine the fifth member of the arithmetic progression, if the sum of the second and fifth members equal to 73, and difference d = 7.
Ravens
On two trees sitting 17 ravens. If 3 ravens flew from first to second tree and 5 ravens took off from second tree then the first tree has 2 times more ravens than second tree. How many ravens was originally on every tree?
Rectangle 35
Find the area of a rectangle when the diagonal is equal to 30 cms and the width is double the length.
The rectangle
Determine the area of the rectangle where the length and width are in the ratio 5:2 and its length is 7.5 cm longer than its width. Determine also its length and its width.

Do you have an interesting mathematical example that you can't solve it? Enter it, and we can try to solve it.