Laura solves a problem in 3 minutes. Alia solves the same problem in $\dfrac{1}{5}$ of the time.
How long does it take Alia to solve the problem?
A.60 seconds
B.36 seconds
C.12 seconds
D.6 seconds

Hint: In this question first convert minutes to second then as mentioned in the question Alia takes one-fifth time less, so proceed accordingly by forming the relation between the two.

Complete step-by-step answer:
Given that Laura solves a problem in 3 minutes and Alia takes one-fifth time to solve the same problem.In one minute there are 60 seconds.
So,
It takes 3 minutes, i.e., 180 seconds by Laura to solve a problem.
Now, as given in the question that Alia takes only one-fifth time to solve the same problem.
So, $180 \times \dfrac{1}{5} = 36$ seconds, to solve the problem by Alia.
So, Alia is $180 - 36 = 144$ seconds faster than Laura.

So, the correct answer is “Option B”.

Note: This is a basic word-problem, as Alia solves one-fifth times faster than Laura, so whatever time is taken by her, if we divide it by five we will get the result.