Question

A mason needs to buy $ 680 $ bricks to build a wall. After laying $ \dfrac{{21}}{{34}} $ of the total bricks, he takes a break. How many bricks remain to be laid to finish the wall?

Answer 1

Hint: For this question, we have to first find the bricks laid by $ 680 $ bricks and this will be done by using the concept of the unitary method. After that, we will subtract the total bricks needed from the bricks required to lay to get the remaining bricks. And through these steps, we will solve this problem.

Complete step-by-step answer:
Here, in the question, it is given that a mason needs to buy $ 680 $ bricks to build a wall and he took a break after laying $ \dfrac{{21}}{{34}} $ the total bricks.
So by using the unitary method,
Since $ \dfrac{{21}}{{34}} $ parts of $ 680 $ bricks laid by a mason
That is on writing the above statement mathematically we have
 $ \Rightarrow \dfrac{{21}}{{34}} \times 680 $
Now on making the above equation, to the simplest form by solving we get the equation as
 $ \Rightarrow 21 \times 20 $
And on solving the multiplication of the above equation, we will get it as
 $ \Rightarrow 420 $
So, $ 420 $ bricks were being laid by the mason before taking the break.
Now we will calculate the remaining bricks,
So for this, we will subtract the total bricks needed from the bricks required to lay to get the remaining bricks.
Therefore, mathematically it will be
 $ \Rightarrow 680 - 420 $
And on solving the subtraction of the above equation, we get the equation as
 $ \Rightarrow 260 $
Hence, $ 260 $ bricks remain to be laid to finish the wall.
So, the correct answer is “260 ”.

Note: So for solving this question we don’t need any formula, what we need is just a little bit of concept of the unitary method and we can easily solve it. In this type of question, we should always read the question carefully as from the question itself we can frame the equation and find the values.