UPSC CDS 1 2022 Math Paper

Concept:
If a cube of a number is negative then the number is also negative,
For example, x=−3
Therefore, x3=−3×−3×−3=−27
Calculation :
x3=−29.8
⇒x=−ve
Now, using equation (2), we get
⇒y3=3x
We know that value of x is negative, so
⇒y3=3(−ve)=−ve
So, y is also negative
Now, if both the terms x and y are negative
Sum of negative terms is always negative
⇒3(−ve)+2(−ve)
⇒−ve
⇒3x+2y is negative.
∴ Both Statement - I and Statement - Il are together sufficient to answer the question.