Frame one problem on time distance and show the solution of it.
on the chapter direct and inverse proportion
Answers
Answer:
EXERCISE: 13.1
1. Followings are the car parking charges near a railway station opto
Check if the parking charges are in direct proportion to the parking time.
Sol. Since
∴ The parking charges are not in direct proportion to the parking time.
2. A mixture of paint is prepared by mixing 1 pan of red pigments with 8 parts of base. In the following table, find the parts of base that need to be added.
Sol. It is given that parts of red pigment, say x and parts of base, say y are in direct proportion. Therefore, the ratio of the correspondng values of x and y remain constant.
So, x and y are in direct variation with the constant of variation equal to . This means that x is of y and y is eight times of x. Thus, the required entries are
3. 3. In question 2 above, if 1 part of a red pigment requires 75 ml. of base, hew much red pigment should we mix with 1800 mL of be.
Sol. Let the parts of red pigmen. required to mix with 1800 ml. of base be x.
The given infonrutlon in the form of a table is as follows.
The parts of red pigment and the parts of base are in direct proportion. Therefore, we obtain
Thus, 24 parts of red pigments shook! be mixed with 1800 mL of base.
4. A machine in a soft drink factory fills 840 bottles in six hours. How many bottles will it fill in five hours?
Sol. Let the number of bottles filled by the machine in five hours be x.
The given information in the form of a table is as follows.
The number of bottles and the time taken to fill these bottles are in direct proportion.
Therefore, we obtain
Thus 700 bottles wtll be filled in 5 hours.
5. A photograph of a bacteria enlarged 50,000 times attains a length of 5 cm as shown in the diagram.
What is the actual length of the bacteria? If the photograph is enlarged 20,000 times only, wnat would be its enlarged length?
Suppose x be the enlarged length of the bacteria when its photograph is enlarged 20000 times.
Then the information can be put in the following tabular form:
Hence, its enlarged length is 2 cm.
6. In a model of a ship, the mast is 9 cm high, while the mast of the actual ship is 12 m high. If the length of the ship is 28 m, how long is the model ship?
Sol. Let the length of the mast of the model ship he x cm. The given information in the form of a table is as follows:
We know that the dimensions of the actual ship and the model ship are directly proportional to each other.