iit permutation

Algebra Level 3

the number of seven digit integers, with sum of the digit equal to 10 & formed by using the digits 1, 2,&3 only, is???? :)


The answer is 77.

Vishal Bansal by Vishal Bansal , 26, India

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

2 solutions

Shivam Garg
Mar 30, 2015

There are two cases possible: Case 1: When we take digits as 1,1,1,1,1,2,3 Numbers possible=7! ÷ 5! = 42 Case 2: When we take digits as 1,1,1,1,2,2,2 Numbers possible= 7! ÷ (4!×3!) = 35 Therefore total numbers possible = 42+35 = 77

0 Helpful 0 Interesting 0 Brilliant 0 Confused

same i did.. :) hehe.. ;)

Vishal Bansal - 6 years, 2 months ago
Vishal Bansal
Mar 30, 2015

there are 2 possible cases - Case 1- five 1's, one2's, one3's therefore numbers=7!/5! =42 Case 2- four 1's, three 2's therefore numbers=7!/4!3! =35 therefore total = 77

0 Helpful 0 Interesting 0 Brilliant 0 Confused

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...