Question

An adult’s toothbrush is 15.5cm long and a child's toothbrush is 13.7cm long. How much longer is an adult toothbrush?

Answer 1

Hint: In the above question, we can see that the toothbrush is longer than the child’s toothbrush, so, the difference between the length of the adult’s toothbrush and child’s toothbrush gives us how much longer an adult’s toothbrush is from a child's toothbrush.

Complete step-by-step answer:
We have been given that an adult toothbrush is 15.5cm long and a child's toothbrush is 13.7cm long, so, we have to find how much longer an adult’s toothbrush is from a child's toothbrush.
We will find the difference between the length of an adult's toothbrush and a child's toothbrush which will give us how much longer an adult’s toothbrush is from the child’s toothbrush.
Now, length of adults toothbrush = 15.5cm
Length of child’s toothbrush = 13.7cm
Difference between the toothbrushes is
\[\begin{align}
  & \Rightarrow \left( 15.5-13.7 \right) \\
 & \Rightarrow 1.8cm \\
\end{align}\]
Therefore, by 1.8cm an adult’s toothbrush is longer than the child's toothbrush.

Note: In any question, if we have been asked how much longer or shorter is something among the two or more things, then, we should always take the difference to find the required value. If we were asked how much shorter is a child’s toothbrush, then also the process and answer would have been the same.