Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and independent equations ensures a solution.

If Fran jumps straight up off the floor and lands on her feet T seconds later, her feet will reach a maximum height of 1.22T^2 meters above the floor. On one such jump, was Fran off the floor for less than 1 second?

(1) On her jump Fran’s feet reached a maximum height of 1 meter above the floor

(2) On her jump Fran spent more than 1/4 second ascending

Modify the original condition and the question. Since her feet will reach a maximum height of 1.22t^2 after t seconds later, you need to figure out t. So, there is 1 variable, which should match with the number of equations. So you need 1 equation. For 1) 1 equation, for 2) 1 equation, which is likely to make D the answer.

For 1), you can find out value of t from 1.22t^2=1, which is sufficient.

For 2), 1/4 second was spent more. So, if it is 1.1/4 seconds, it is yes. If it is 1 second, it is no and not sufficient. Therefore, the answer is A.

-> For cases where we need 1 more equation, such as original conditions with “1 variable”, or “2 variables and 1 equation”, or “3 variables and 2 equations”, we have 1 equation each in both 1) and 2). Therefore, there is 59 % chance that D is the answer, while A or B has 38% chance and C or E has 3% chance. Since D is most likely to be the answer using 1) and 2) separately according to DS definition. Obviously there may be cases where the answer is A, B, C or E.

_________________

MathRevolution: Finish GMAT Quant Section with 10 minutes to spare

The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.

"Only $99 for 3 month Online Course"

"Free Resources-30 day online access & Diagnostic Test"

"Unlimited Access to over 120 free video lessons - try it yourself"