CTET 2 Math and Science 21 Jan 2024 Paper

Question : 37 of 150

Marks: +1, -0

A student was given the following problem on percentage to solve,
“Find the percentage of decrease if the population of a city decreased from 28,000 to 26,500.”
She wrote the following solution,
Original population = 28,000; New population = 26,500
% decrease =

\;{26,500}/{28,000} × 100\% = 94.6\%

Which of the following is most appropriate with respect to the response of the student?

Student has made a careless mistake.
Student can understand the concept of percentage but is not able to understand the percentage of which quantity is to be found.
Student has solved the question correctly but has used wrong symbols in solution.
Student does not know the concept of percentage.

Validate

Solution:

The correct calculation should have been:
- Percentage decrease

\;=( 2 8 0 0 0 - 2 6 5 0 0 \/ 2 8 0 0 0 ) × 1 0 0 \%

\;=( 1 5 0 0 \/ 2 8 0 0 0 ) × 1 0 0 \%

\;= 5 . 3 6 \%

So, while the student understands the concept of finding a percentage decrease, they made a calculation mistake, possibly by dividing the wrong way, resulting in an incorrect answer.
The correct answer is Students can understand the concept of percentage but are not able to understand the percentage of which quantity is to be found.

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