Kinshook wrote:
Bunuel wrote:
GMAT CLUB'S CHALLENGE QUESTIONS:
How many positive four-digit integers have their digits in ascending order from thousands to units?
A. 6
B. 7
C. 84
D. 126
E. 210
If we select 4 numbers out of 10 and deselect numbers with 0 as thousandth digit.
10C4 - 9C3 = 126
IMOD
Why do we take combinations? I mean the order is important right(ascending) so shouldn't it be permutation?
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