Question

If the Pacific Ocean is widening at a rate of \[5cm\] per year, how far (in kilometres) will it spread in two million years?
\[\begin{align}
  & 5cm=\_\_m=\_\_\_\_\_km \\
 & 1million=\_\_\_\_\_ \\
 & 2million=\_\_\_\_\_\_\_ \\
\end{align}\]

Answer 1

Hint: From the question given, it has been given that the Pacific Ocean is widening at a rate of \[5cm\] per year. We have been asked to find how far it will spread in two million years. First of all, we can clearly observe that the widening rate is given in \[cm\]. So, now we have to convert it into kilometres.

Complete step by step solution:
Now considering from the question it is given that the Pacific Ocean is widening at a rate of $5cm$ per year.
So, according to the process, let us first convert the widening rate \[5cm\]into kilometres.
\[5cm=5\times {{10}^{-2}}m=5\times {{10}^{-5}}km\]
Also, we know that one million is equal to \[{{10}^{6}}\].
Now, let us calculate, in one million years how much the Pacific Ocean will expand,
We have been already given the question that the Pacific Ocean is widening at a range of \[5cm\] per year.
In one million years it will be:
\[{{10}^{6}}\times 5\times {{10}^{-5}}=5\times {{10}^{1}}=50\]
Therefore, in one million years, the Pacific Ocean will expand \[50km\].
Now, in the given question we have been asked to find how far it will spread in two million years.
In two million years it will be: \[2\times {{10}^{6}}\times 5\times {{10}^{-5}}=2\times 5\times {{10}^{1}}=2\times 50=100\]

Therefore, in two million years, the Pacific Ocean will expand \[100km\].

Note: We should be very careful while converting the units. We should not get confused while converting the units. We should understand the given question thoroughly to get the exact answer for the given question. We should be well aware of converting centimetres into kilometres. We should be very careful while doing the calculation. We should remember that $100cm=1m$ and $1000m=1km$ .