Question

There are $ 5miles $ to $ 8km $ . Then how many $ km $ in $ 80miles $ ?

Answer 1

Hint :Here, it is important to know that the miles and kilometer comparison is already given and we have to find out what $ 1mile $ in kilometers is and we must understand the conversion between both the units.

Complete Step By Step Answer:
Let us first consider the relation between miles and kilometers as given in the above question from that conversion we have as given below is:
 $ 5miles \to 8km $ …. ( given )
So the $ 1mile $ is written as
 $ 1mile \to \dfrac{8}{5}km $ …. $ (1) $
As we have found out what $ 1mile $ is equal to we can derive the conversion of any miles to km as follows
From $ (1) $ , we have
 $ 1mile \to \dfrac{8}{5}km $
Now we want the conversion of $ 80miles $ to kilometers, as follows
 $ 80miles = 80 \times 1mile $
 $ \Rightarrow 80miles = 80 \times \dfrac{8}{5}km $
On solving this equation above, we get
 $ \Rightarrow 80miles = 16 \times 8km = 128kms $
Hence we have calculated the conversion of $ 80miles $ to $ 128kms $ .

Note :
In the above question we have been already given the conversion of mile to km, from this given information we are able to calculate what is the smallest part of the $ 5miles $ i.e. $ 1mile $ can be in kilometers. Similarly, we have used this conversion to find out the value like $ 80miles $ . But if we do not have the smallest part known or we cannot calculate the smallest part then it would be difficult for us to find the bigger conversions from miles to kilometers. In the above given procedure we have to understand the comparison and find out the required value.