Elitmus
Exam
Numerical Ability
Number System
How many three digit positive integer,with digit x,y and z in the hundreds,tens and units place respectively,exist such that x
Read Solution (Total 4)
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- How many three digit positive integers, with digits x, y and z in the hundred’s, ten’s and unit’s place respectively, exist such that x < y, z < y and x ≠ 0?
(A) 240
(B) 245
(C) 285
(D) 320
(E) 720
The middle digit y can take values from 2-9
when y is 9 x can take values from 1-8 and z can take values from 0-8
Total num = 8*9
when y is 8 x can take values from 1-7 and z can take values from 0-7
Total num = 7*8
....
Total num = 9*8+8*7+7*6+6*5+5*4+4*3+3*2+2*1 =240 - 6 years agoHelpfull: Yes(25) No(1)
- Total positive integer 240
- 7 years agoHelpfull: Yes(2) No(2)
- x
- 7 years agoHelpfull: Yes(0) No(7)
- x
- 7 years agoHelpfull: Yes(0) No(2)
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