The marks obtained by Rani in her twelfth standard exams are tabulated below. Express these marks as percentage.

Hint: To find the percentage use formula, $\text{percentage=}\dfrac{\text{marks obtained}}{\text{total marks}}\text{ }\!\!\times\!\!\text{ 100}$. Divide the obtained marks with total marks and multiply it with 100 to get the percentage of marks obtained in a particular subject.

“Complete step-by-step answer:”
In mathematics, a percentage (from Latin percentum “by a hundred”) is a number or ratio expressed as a fraction of 100. It is often denoted by using the percent sign, “%”, or the abbreviations “pct.”, “pct” sometimes the abbreviation “pc” is also used. A percentage is a dimensionless number or pure number. For example: 45% is equal to $\dfrac{45}{100}$, $45:100$ or $0.45$. Percentages are often used to express a proportionate part of a total.
Now, we come to the question. Therefore,
(i) Percentage of marks obtained in English
$
 =\dfrac{\text{marks obtained in english}}{\text{maximum marks in english}}\times 100\% \\
 =\dfrac{180}{200}\times 100\% \\
 =90\% \\
$

(ii) Percentage of marks obtained in Tamil
 $
 =\dfrac{\text{marks obtained in tamil}}{\text{maximum marks in tamil}}\times 100\% \\
 =\dfrac{188}{200}\times 100\% \\
  =94\% \\
$

(iii) Percentage of marks obtained in Mathematics
$
  =\dfrac{\text{marks obtained in mathematics}}{\text{maximum marks in mathematics}}\times 100\% \\
  =\dfrac{195}{200}\times 100\% \\
  =97.5\% \\
$

(iv) Percentage of marks obtained in Physics
$
  =\dfrac{\text{marks obtained in physics}}{\text{maximum marks in physics}}\times 100\% \\
  =\dfrac{132}{150}\times 100\% \\
  =88\% \\
$

(v) Percentage of marks obtained in Chemistry
$
  =\dfrac{\text{marks obtained in chemistry}}{\text{maximum marks in chemistry}}\times 100\% \\
  =\dfrac{142}{150}\times 100\% \\
  = 94.67\% \\
$

(vi) Percentage of marks obtained in Biology
$
  =\dfrac{\text{marks obtained in biology}}{\text{maximum marks in biology}}\times 100\% \\
  =\dfrac{140}{150}\times 100\% \\
  =93.33\% \\
$

Hence, the required table of marks is shown as:

Note: Don’t take the ratio of marks inversely because in that case you will get the percentage obtained greater than 100 which is not possible. Percentage value is either less than 100 or maximum 100.