# Direct proportionality - practice problems

Two sequences of numbers are proportional if their corresponding elements have a constant ratio. Direct proportionality is the dependence of two quantities, such that the number of times one quantity increases, the other quantity increases as many times. In other words: direct proportionality is a relationship in which it applies: in what proportion one quantity changes, in that proportion the other quantity also changes.For example:

For 1 euro, I buy 10 rolls, then for 2 euros I buy 20 rolls in the same store.

A car travels at a constant speed, then the distance traveled is directly proportional to the time spent traveling, with the speed being the constant of proportionality.

#### Number of problems found: 632

- Numbers at ratio 2

Two numbers are in the ratio 3:5. If each number is increased by 10, the ratio becomes 5:7. Find the sum of the numbers. - Gasoline 15

A car consumes 8 liters of gasoline for 20km. How far can it go for 36 liters? - A park on map

A park has an area of ⅙ mi². On a map, the park has an area of 1 ¼ cm². On the map, how many square centimeters represent 1 mi²? - Proportional relationship 3

Which table below shows a proportional relationship? A. x ; y 3; 12 4; 16 5; 20 6; 24 7; 28 B. x ; y 3; 15 4; 20 5; 25 6; 35 7; 40 C. x ; y 3; 24 4; 32 5; 45 6; 48 7; 56 D. x ; y 3 ; 21 4; 24 5; 35 6; 42 7; 49

- The capacitor

The parallel square plates of a 4.5µF Teflon capacitor are 3.2 mm apart. What is the area of the plate? - The restaurant

The restaurant is 3/8 miles from the office. She makes the walk in 7 1/2 minutes. At the same rate, how long will it take her to walk the two miles from her home to her office? - Unit price 3

A grocery store sells a bag of 6 oranges for $5.64. How much would it cost for 8 oranges? - Miniature train

Allen's miniature train travels at a rate of 20 meters in 2 minutes. At this rate, how far will the train travel in 10 minutes? - It takes 2

It takes 7 1/5 seconds for a jet to fly 1 km. How long does it take for this jet to fly 3/4 of a km?

- The intensity

The light intensity on a screen is inversely proportional to the square of the distance between the screen and the light source. If a screen is illuminated by a light source 20 m away, the intensity is one-fifth of what is required. Where should the light - Glue strength

At 40°C, it takes 3 hrs to get 125% glue strength. How long does it take to get 100% at 50 ˚C? The higher the temperature, the faster it cures the glue. - Two similar 2

Two similar polygons have corresponding sides 15 inches and 6 inches. If the area of the first is 2700 square inches, what is the area of the second? - Circle graph

Erica surveyed students at her school about their favorite type of music. She made a circle graph to show the results. The central angle for the section of the graph that represents country music measures 72°. If 45 classmates chose the country as their f - David 5

David was riding his bicycle at a speed of 26.5 kilometers per hour (km/h). Use the fact that 1 kilometer is approximately equal to 0.6214 miles to convert this speed to miles per hour (mile/h)

- Inheritances

According to a will, the inheritance is to be divided among 2 sons and 1 daughter. The ratio of the amount given to the eldest son to the amount given to the daughter is 2:1 the ratio of the amount given to the youngest son to the amount given to the daug - A statue

A statue on a shelf is recreated on a computer screen. The actual statue is 14 in. tall and 4 in. wide. The statue on the computer screen is 1.5 in. wide. How tall is the statue on the computer screen? - Employees 16

There are 3 full-time employees in your office for every 5 who are part-time. If there are 25 part-time employees, how many full-time employees are there? - The distance 3

The distance covered by car in 1 hour is 38 1/2 km. Find the distance it will cover in a) 3 1/2 hours, b) 5 hours. - Percentage 83199

The selling price is 5.75 EUR, and the buying price is 4 EUR. By what percentage was the price increased?

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