General Aptitude - 27.2 Problems on Numbers - Data Sufficiency 1 Free Online Tests | Mock Tests | Preparation | Practice Tests

Goto

Take Exam

01 02 03 04

2 / 4

What is the two-digit number?
I.	The difference between the two digits is 9.
II.	The sum of the digits is equal to the difference between the two digits.

A. I alone sufficient while II alone not sufficient to answer

B. II alone sufficient while I alone not sufficient to answer

C. Either I or II alone sufficient to answer

D. Both I and II are necessary to answer

E. None of the above

View Answer

Correct choice: D

Explanation:

Let the tens and unit digits be x and y respectively. Then,

I. x - y = 9.

II. x + y = x - y.

From I and II, we get x - y = 9 and x + y = 9.

On solving, we get x = 9 and y = 0.

∴ Required number is 90.

Thus, both I and II are needed to get the answer.

∴ Correct answer is (E).

2 / 4

Lessons