Question

There are 100 MBA aspirants in a classroom and 99% of them are engineers. How many engineers must leave the classroom in order to reduce the percentage of engineers in the classroom to 98%?

• A. 1
• B. 2
• C. 50
• D. 90

Hint:

The one non-engineer in the room never leaves, so use that fixed count to find the new total when engineers drop to 98%.

Answer 1

The Correct Option is C

Step 1: Find the number of non-engineers, since that number never changes.
Out of 100 students, 99% are engineers, so there are 99 engineers and only \(100 - 99 = 1\) non-engineer. Only engineers leave the room, so this 1 non-engineer count stays fixed the whole time.

Step 2: Use the fixed non-engineer count to set up the new total.
After some engineers leave, non-engineers must make up \(100\% - 98\% = 2\%\) of whatever students remain, because engineers are then 98% of the new total.

Step 3: Turn the percentage into an equation.
If the new total number of students is \(T\), then 2% of \(T\) equals the fixed 1 non-engineer: \(0.02 \times T = 1\), so \(T = 50\).

Step 4: Find how many students, and so how many engineers, left.
The room started with 100 students and now has 50, so 50 students left. Since only engineers left the room, all 50 who left were engineers.

Final Answer:
\[ \boxed{50 \text{ engineers must leave}} \]