If we fix time period and the rate of interest, simple interest changes proportionally with principal. Would there be a similar relationship for compound interest? Why?
For simple interest,
∵ Simple interest =
∴
Since rate and time period are constant, then SI directly according to P.
Thus, the simple interest changes in direct proportion with the principal.
For compound interest.
∵ Compound interest =
∴
Since, rate and time period are constant, then
is constant.
i.e. CI changes with P
Thus, the compound interest also changes directly in proportion with principal.
A mixture of paint is prepared by mixing 1 part of red pigments with 8 parts of base. In the following table, find the parts of base that need to be added.
In question 2 above, if 1 part of a red pigment requires 75 mL of base, how much red pigment should we mix with 1800 mL of base?
A machine in a soft drink factory fills 840 bottles in six hours. How many bottles will it fill in five hours?
Number of bottles filled |
Number of hours |
840 |
6 |
X |
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, what would be its enlarged length?
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 28m, how long is the model ship?
Suppose 2 kg of sugar contains 9 x 106 crystals. How many sugar crystals are there in (i) 5 kg of sugar? and (ii) 1.2 kg of sugar?
Rashmi has a road map with a scale of 1 cm representing 18 km. She drives on a road for 72 km. What would be her distance covered in the map?
A 5 m 60 cm high vertical pole casts a shadow 3 m 20 cm long. Find at the same time (i) the length of the shadow cast by another pole 10 m 50 cm high and (ii) the height of a pole which casts a shadow 5 m long.