Latest Elitmus Aptitude Question SOLUTION: How many no can be formed using digits (1,2,3,4,5,6,7,8,9)..such that they are in increasing order?

• Placement Papers
• /
• Elitmus
• /
• Category

Elitmus Question Papers:

(#M40151325) ELITMUS Category question Keep an EYE

How many no can be formed using digits (1,2,3,4,5,6,7,8,9)..such that they are in increasing order?

Asked In Elitmus sangrambadi sahoo (9 years ago)

Unsolved Read Solution (4)

Is this Puzzle helpful?   (11)   (5) Submit Your Solution

Read Solution (4) :

Priya Pandey  (9 years ago)

Consider the string 123456789. Observe that each of the 9 digits in the string can safely be either included or not included, since failing to include a digit will not violate the increasing order of the digits. Hence, there are 29 possible strings that contain (0 or 1 or 2 or ... or 9) digits. However, we likely want to omit the case where there are 0 digits, which leaves us with a final answer of:

2^9 -1 = 511

Is this solution Helpfull? Yes (5) | No   

AWDHESH CHAUHAN  (9 years ago)

if we include all no at a time then only one no is possible 1 2 3 4 5 6 7 8 9

Is this solution Helpfull? Yes (3) | No (2)  

saurabh  (9 years ago)

i think 502 is the answer as in the last sol i have only consider case for 3 digit no bt there can be any no which includes 2,3,4...9 digit no

Is this solution Helpfull? Yes (2) | No   

saurabh  (9 years ago)

i think 9c3=84 is the answer as there is only one way to arrange the order.

Is this solution Helpfull? Yes | No (3)  

Please Login to Read Solution.