Advertisements
Advertisements
प्रश्न
Find the value of n if `1/(8!) + 1/(9!) = "n"/(10!)`
Advertisements
उत्तर
`1/(8!) + 1/(9!) = "n"/(10!)`
`1/(8!) + 1/(9 xx 8!) = "n"/(10 xx 9 xx 8!)`
Multiplying thrughout by 8!
`1 + 1/9 = "n"/(10 xx 9)`
`(9 + 1)/9 = "n"/(10 xx 9)`
`"n"/(10 xx 9) = 10/9`
n = `10/9 xx 10 xx 9`
= 100
⇒ n = 100
APPEARS IN
संबंधित प्रश्न
How many two-letter words can be formed using letters from the word SPACE, when repetition of letters is not allowed?
How many numbers between 100 and 1000 have 4 in the units place?
A Signal is generated from 2 flags by putting one flag above the other. If 4 flags of different colours are available, how many different signals can be generated?
How many five-digit numbers formed using the digit 0, 1, 2, 3, 4, 5 are divisible by 5 if digits are not repeated?
Count the numbers between 999 and 10000 subject to the condition that there are at least one of the digits is repeated
How many numbers are there between 1 and 1000 (both inclusive) which are divisible neither by 2 nor by 5?
How many strings can be formed using the letters of the word LOTUS if the word neither starts with L nor ends with S?
Find the value of 4! + 5!
Find the value of 3! – 2!
Find the value of n if (n + 1)! = 20(n − 1)!
Choose the correct alternative:
The number of ways in which the following prize be given to a class of 30 boys first and second in mathematics, first and second in physics, first in chemistry and first in English is
Choose the correct alternative:
The number of 5 digit numbers all digits of which are odd i
Choose the correct alternative:
There are 10 points in a plane and 4 of them are collinear. The number of straight lines joining any two points is
If the letters of the word RACHIT are arranged in all possible ways as listed in dictionary. Then what is the rank of the word RACHIT?
Find the number of integers greater than 7000 that can be formed with the digits 3, 5, 7, 8 and 9 where no digits are repeated.
The sum of the digits in unit place of all the numbers formed with the help of 3, 4, 5 and 6 taken all at a time is ______.
The number of six-digit numbers, all digits of which are odd is ______.
In a steamer there are stalls for 12 animals, and there are horses, cows and calves (not less than 12 each) ready to be shipped. They can be loaded in 312 ways.
If the number of five-digit numbers with distinct digits and 2 at the 10th place is 336 k, then k is equal to ______.
