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?
A cyclist passes 88 km in 4 hours. How many kilometers he pass in 8 hours?
4 chickens give 4 eggs in 4 days. How many eggs can give 8 chickens for 8 days?
- 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)
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?
Two cats caught two mice in two days. How many mouses will catch 6 cats for 6 days?
- Efficiency of rail
With subsidies are business easy. Calculate how much must cost rail ticket (x) in today's ticket price € 13 and if the trains was not subsidized, if it is known that without subsidies would cost three times today's ticket prices. Calculate the value of.
Gross wage was 1113 USD including 16% bonus. How many USD were bonuses?
- Daily average
Calculate the average temperature during the day, when 14 hours was 20 °C and 10 hours was 15 °C.
- 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
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.
Unfold number 4712 in the ratio 10:14:7.
Calculate how many average minutes a year is the web server is unavailable, the availability is 99.99%.
6 pump fills the tank for 3 and a half days. How long will fill the tank 7 equally powerful pumps?
- 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?
Product has been discounted twice by 14%. What is the total discount given?
- DIY press
Under socialism regime was in some socialist countries to own a typewriter requires special permission. That has hindered the spread of DIY literature (manually transcribed through carbon copy paper for typewriters). Calculate how many typewriters today.
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?
- The horses
A couple of horses consume 88 kg of oats for 14 days. How many oats consumed 7 horses at the same consumption for 6 days?
800 pennies have the same value as 100 ducats. 100 pennies have the same value as 250 tolars. How many ducats has the same value as 100 tolars?