Examples for 8th grade - page 14
Buses Ikarus and Karosa simultaneously started at 11:00 from the final station. Ikarus is returned to the station after 30 minutes. Karosa after 45 minutes. At what time both buses again returned to the station?
- Washing machine
The price of washing machine was decreased by 24% and then by 59 € due small sales. After two price decreases cost € 300. How much was originally cost?
- Ladislav in Amsterdam
Ladislav was reward and went to conference in Amsterdam. Conferense fee was € 2184. Calculate how many books Ladislav could buy at the price of 42 and 28 euros if he don't want fill whole home library and he can buy only 63 books?
Calculate the length of the arm r of isosceles triangle ABC, with base |AB| = 16 cm and a height v=10 cm.
- Newton's task
Grass grows in the meadow equally fast and evenly. It is known that 58 cows graze meadow for 30 days and 80 cows by 19 days. How many cows graze meadow for 6 days?
In the center of the cube with edge 15 cm we will drill cylinder shape hole. Volume of the hole must be 28% of the cube. What drill diameter should be chosen?
- Bits, bytes
Calculate how many different numbers can be encoded in 16-bit binary word?
The first harvester reaps the grain from land for 24 hours, the second harvester for 16 hours. For how many hours will take harvest by two harvesters, but the second harvester started working four hours later than the first?
I have a box with two hundred pieces of gloves in total, split into ten parcels of twenty pieces, and I sell three parcels. What percent of the total amount I sold?
- Gold coin
Gold coin contains 963 promile pure gold, which is 8.39 g. What is the weight of coin in grams?
Father collects strawberries himself in 4 hours, son in 10 hours. How long will it take them along when dad comes to help son collect strawberries after 4 hours?
The boys from scout group traveled 3 days distance 105 km. Every day walked 1.3 km less than the previous day. How many kilometers scouts walked in the first day?
The first team of painters would paint bridge in 15 days, the second in 10 days. After 3 days of working together second team goes out and continue only first team. How many days took second team to finish painting the bridge?
For horizontal distance 3 km road rise by 5.4 m. Calculate the road pitch in ‰ (permille, parts per thousand).
- Inflow - outflow
The tank will fill by inflow for 93 minutes and empties by outflow for 104 minutes. How long take to fill tank if it is also opened the inflow and outflow?
Find all divisors of number 418. How many are them?
- Degrees to radians
Convert magnitude of the angle α = 618°40'29" to radians:
- Two pumps
The first pump fills the tank in 24 hours second pump in another 40 hours. For how long will take fill the tank if operate both pumps at the same time?
8 girls wants to play volleyball against boys. On the field at one time can be six players per team. How many initial teams of this girls may trainer to choose?
- Apples 2
James has 13 apples. It has 30 percent more apples than Sam. How many apples has Sam?