EASY
JEE Main/Advance
IMPORTANT
Earn 100
white counters and red counters are arranged in a straight line with counters on each side of a central mark. The number of ways of arranging the counters, so that the arrangements are symmetrical with respect to the central mark is
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Important Questions on Permutation and Combination
MEDIUM
JEE Main/Advance
IMPORTANT
Among the permutations of the digits , consider those arrangements which have the following property. If we take any five consecutive positions, the product of the digits in these positions is divisible by The number of such arrangements is equal to
HARD
JEE Main/Advance
IMPORTANT
The total number of times, the digit will be written, when the integers having less than digits are listed is equal to
HARD
JEE Main/Advance
IMPORTANT
There are white and black balls, each set numbered to . The number of ways in which the balls can be arranged in a row, so that the adjacent balls are of different colors is
HARD
JEE Main/Advance
IMPORTANT
A train timetable must be compiled for various days of the week so that two trains twice a day depart for three days, one train daily for two days, and three trains once a day for two days. How many different timetables can be compiled ?
MEDIUM
JEE Main/Advance
IMPORTANT
A seven-digit number without repetition and divisible by is to be formed by using seven digits out of The number of ways in which this can be done is
MEDIUM
JEE Main/Advance
IMPORTANT
The number of distinct natural numbers up to a maximum of four digits and divisible by which can be formed with the digits , each digit not occurring more than once in each number, is
MEDIUM
JEE Main/Advance
IMPORTANT
If then is equal to
MEDIUM
JEE Main/Advance
IMPORTANT
If then
