Ratio + multiplication - examplesOn solving problems and tasks with proportionally we recommend hint rule of three. Rule of three (proportionality) help solve examples of direct and inverse proportionality. Three members makes possible to calculate the fourth - unknown member.
Charlie bought 7 same chocolates for 14 Eur. How many euros he pay for 27 chocolates?
- Forestry workers
In the forest is employed 63 laborers planting trees in nurseries. For 11 hour work day would end job in 43 days. After 14 days, 22 laborers go forth. How many days is needed to complete a planting trees in nurseries by others, if they will work 15 hours
Gross wage was 1113 USD including 16% bonus. How many USD were bonuses?
- Motion problem
From Bratislavy to Martina go car at speed 83 km/h. From Martina to Bratislavy go another car at speed 62 km/h. How many minutes before the meeting will be cars 21 km away?
A cyclist passes 88 km in 4 hours. How many kilometers he pass in 8 hours?
One meter of the textile were discounted by 2.4 USD. Now 6 m of textile cost as before 3 m. Calculate the old and new price of 1 m of the textile.
If you go at speed 6.6 km/h, you come to the station 51 minutes after leaving train. If you go by bike to the station at speed 30 km/h, you come to the station 45 minutes before its departure. How far is the train station?
Calculate how many average minutes a year is the web server is unavailable, the availability is 99.99%.
In human body the blood is about 7.7% body weight. How many kilograms of blood is in the human body with weight 96 kg?
4 chickens give 4 eggs in 4 days. How many eggs can give 8 chickens for 8 days?
The observer sees straight fence 100 m long in 30° view angle. From one end of the fence is 119 m. How far is it from the another end of the fence?
Calculate fixed annual personnel costs of operating monorail line 106 km long if every 5 km is station, which serve three people - one dispatcher and two switchman in 3-shift operation. Consider the average salary of the employee 847 €.
- Youth track
Youth track from Hronská Dúbrava to Banská Štiavnica which announced cancellation attracted considerable media attention and public opposition, has cost 6.3 euro per capita and revenue 13 cents per capita. Calculate size of subsidies to trip group of 17.
- School trip
School trip cost 340.8 USD for one class (24 students). How much would cost a trip for two classes? (both classes together have 44 students)
Determine the number of all positive integers less than 2937474 if each is divisible by 11, 23, 17. What is its sum?
Two cats caught two mice in two days. How many mouses will catch 6 cats for 6 days?
- Daily average
Calculate the average temperature during the day, when 14 hours was 20 °C and 10 hours was 15 °C.
- Gear wheels
Two gear wheels, which fit together have number of teeth z1=132 and z2=123. Calculate the speed of the first wheel, if the second wheel rotates 247 revolutions per minute.
- Profitable bank deposit 2012
Calculate the value of what money lose creditor with a deposit € 7700 for 4 years if the entire duration are interest 2.2% p.a. and tax on interest is 19% and annual inflation is 3.6% (Calculate what you will lose if you leave money lying idle at negative
Product has been discounted twice by 14%. What is the total discount given?