The Usual Method
Simplifying the numerator of the equation, we get:
Hence numerator is
Similarly, simplifying the denominator, we get:
Thus the equation now becomes:
This can be written as:
Estimated Time to arrive at the answer = 150 seconds.
Simply observe that since all the terms in the numerator are positive, simplifying the numerator will also give all positive terms.
The denominator has a negative sign. However, the process of rationalization would require its conjugate to be multiplied to result in a rational number in the denominator. This conjugate multiplier will have positive terms. Hence, when it multiplies with the all positive term numerator, we will get a product in the numerator with all positive terms. The only option that has all positive terms in the numerator is option ‘5’.
Estimated Time to arrive at the answer = 15 seconds.