Question 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?
Answer:Let the length of the mast of the model ship bexcm.
The given information in the form of a table is as follows:

Height of mast
Length of ship
Model ship
9 cm
x
Actual ship
12 m
28 m
We know that the dimensions of the actual ship and the model ship are directly proportional to each other.
Therefore, we obtain:
Thus, the length of the model ship is 21 cm.
in the answer why do we leave some units in m and some in cm .is it not mistake to do that.
In this case we are dealing with the ratio . Here in both the cases real boat is in metre and model is in cm . So this ratio is 1m : 1cm in both . so these will cancel out each other and have no effect on the solution . However you can first convert it into cm and then proceed to calculation also.