Question

The length, $l$ meters, of a garden is 78.5m, correct to the nearest half meter.
Correct this statement about the value of $l$.
$................... \leqslant l \leqslant ...............$

Answer 1

Hint: Add & subtract half meter to get the range.

Complete step-by-step answer:
It is given that the length of the garden which is 78.5m is correct up to half meter.
So, the range of length of the garden can be written as $\left( {78.5 \pm \dfrac{1}{2}} \right)m$

So,
$
  {l}_{1} = 78.5 - \dfrac{1}{2} = 78.5 - 0.5 = 78m \\
  {l}_{2} = 78.5 + \dfrac{1}{2} = 78.5 + 0.5 = 79m \\
$
So, the length of the garden is greater than equal to 78m and less than equal to 79m.
Therefore length $\left( l \right)$ of garden correct up to half meter is written as
$78 \leqslant l \leqslant 79$
So, this is the required answer.

Note: In these types of questions, add and subtract half meter to the value given in question, so that we can get the required range.