Latest Elitmus Aptitude Question SOLUTION: how many 3 digit no.s can be formed so that the sum of two digits will be equal to the third digit?????

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(#M40064042) ELITMUS Numerical Ability question PnC Keep an EYE

how many 3 digit no.s can be formed so that the sum of two digits will be equal to the third digit?????

Asked In Elitmus mudit bahl (10 years ago)

Unsolved Read Solution (28)

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Read Solution (28) :

Rahul Middha  (10 years ago)

Correction to My Last Answer

You Can have These possible cases:
112
224
336
448

These four can be arranged in 12 ways (each in 3 ways) Right.

Also

123
134
145
156
167
178
189
235
246
257
268
279
347
358
369

Also You can Have 101,202 Upto 909. & These 9 numbers can be written in 2 ways each so total 18 ways

459

These 16 can be arranged in 96 ways (each in 6 ways).

So Total No.s will be 96+12+18=126 Ans.

Is this solution Helpfull? Yes (41) | No (1)  

shishir  (10 years ago)

66 is the rght ans.

Is this solution Helpfull? Yes (9) | No (9)  

Mithun Kumar Kesari  (10 years ago)

possible combinations and their arrangements are
(1,1,0)=2, (2,2,0)=2, (2,1,1)=3, (3,3,0)=2, (3,2,1)=6, (4,4,0)=2, (4,3,1)=6, (4,2,2)=3,
(5,5,0)=2, (5,4,1)=6 (5,3,2)=6, (6,6,0)=2 (6,5,1)=6 (6,4,2)=6 (6,33)=3
( 7,7,0)=2 (7,6,1)=6 (7,5,2)= 6 (7,4,3)=6 (8,8,0)=2 (8,7,1)=6 (8,6,2)=6 (8,5,3)=6
(8,4,4)=3 (9,9,0)=2 (9,8,1)= 6 (9,7,2)=6 (9,6,3)=6 (9,5,4)=6

so, total number possible = 16*6 + 4*3 + 9*2= 126 -------ans

Is this solution Helpfull? Yes (6) | No (1)  

Shweta Jha  (10 years ago)

101,202..909.. total=9
112,224,336,448, ways to arrange each=3, total=3*4=12
123,134,145...189, ways to arrange 3!, total=3!*7=42
similarly
235,246...279, total=3!*5=30
347,358,369, total=3!*3=18
459-3!=6

total=117

Is this solution Helpfull? Yes (5) | No (4)  

sunil sharma  (10 years ago)

45 is correct answer because 1st 2 digit equals to the third digits

Is this solution Helpfull? Yes (4) | No (2)  

Gautam Raj  (10 years ago)

Mudit bhai kya answer tick kiya hai
mera 78 aa rha hai....

Is this solution Helpfull? Yes (3) | No (1)  

ASHISH MUKHERJEE  (10 years ago)

Ans must be 72.
check from 100 to 999.

Is this solution Helpfull? Yes (2) | No   

surabhi sugandha  (9 years ago)

126 is the correct answer.... 9*2+4*(3!/2!)+16*6=126

Is this solution Helpfull? Yes (2) | No   

Manish Tiwari  (10 years ago)

The answer will be 78

Is this solution Helpfull? Yes (1) | No (1)  

Rahul Middha  (10 years ago)

You Can have These possible cases:
112
224
336
448

These four can be arranged in 12 ways (each in 3 ways) Right.

Also

123
134
145
156
167
178
189
235
246
257
268
279
347
358
369
459

These 16 can be arranged in 96 ways (each in 6 ways).

So Total No.s will be 96+12=108 Ans.

Is this solution Helpfull? Yes (1) | No (2)  

MADHVI GUPTA  (9 years ago)

frns.......what is the correct ans.....??????

Is this solution Helpfull? Yes (1) | No   

Pranjal Shrivastava  (9 years ago)

3 Digit no. will start from 100-999
100-199: 1st place is for 1,second could be any of 0,1,2,3,4,5,6,7,8, 3rd could be 1,2,3,4,5,6,7,8,9=1*9*9 cases.=81
200-299:2nd place is for 2,second could be any of 0,1,2,3,4,5,6,7, 3rd could be 2,3,4,5,6,7,8,9=1*8*8 cases.=64
300-399:2nd place is for 3,second could be any of 0,1,2,3,4,5,6 3rd could be 3,4,5,6,7,8,9=1*7*7 cases.=49
400-499:2nd place is for 4,second could be any of 0,1,2,3,4,5, 3rd could be 4,5,6,7,8,9=1*6*6 cases.=36
500-599:2nd place is for 5,second could be any of 0,1,2,3,4, 3rd could be 5,6,7,8,9=1*5*5 cases.=25
600-699:2nd place is for 6,second could be any of 0,1,2,3, 3rd could be 6,7,8,9=1*4*4 cases.=16
700-799:2nd place is for 7,second could be any of 0,1,2 3rd could be 7,8,9=1*3*3 cases.=9
800-899:2nd place is for 8,second could be any of 0,1,rd could be 8,9=1*2*2 cases.=4
900-999:2nd place is for 9,second will be 0 3rd will be,9=1*1*1 cases.=1
Total will be 81+64+49+36+25+16+9+4+1=285.

Is this solution Helpfull? Yes (1) | No (1)  

praveendas  (9 years ago)

8+7+.....+1=36

Is this solution Helpfull? Yes (1) | No (1)  

mudit bahl  (10 years ago)

@gautam raj- 78 to ans hi ni tha chcha..... :P

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Mithun Kumar Kesari  (10 years ago)

54 answer

Is this solution Helpfull? Yes | No (2)  

maharaja  (10 years ago)

my answer is 35...

Is this solution Helpfull? Yes | No (1)  

kaustubh salunke  (9 years ago)

102 is the ans

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mamatha spandana parakula  (9 years ago)

0 combination like 10,20----are 9 numbers
1 combination like 11,12,13,----1,8 are 15 numbers
2 combination like 22,23,----27 are 9 numbers
3 combination like 33,34---36 are 7 numbers
4 combination like 44,45 --54 are 3 numbers
3+7+9+15+9=43 is ans

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RAVISH KUMAR  (9 years ago)

for 1st place we have 9 way
for 2nd place we have 10 way
and for 3rd place we have 8! way
so total numbers=9*10*8!

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Harshal Nigam  (9 years ago)

Ans is 45

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abhishek  (9 years ago)

126 explain

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sekhar  (9 years ago)

Its 126 . I have written simple program for this . hope it will help you. Execute the following code.

#include
void main()
{
int n=100,x,i,j,k,c=0;

while(n

Is this solution Helpfull? Yes | No (3)  

Prashant Saini  (9 years ago)

@Rahul Midha and Mithun kumar kesari... bros.... Your answer is perfect.. i.e 126.

Is this solution Helpfull? Yes | No (2)  

NIKHIL RANAJN  (9 years ago)

126 is the correct ans

Is this solution Helpfull? Yes | No (1)  

jitendra singh  (9 years ago)

45 is the correct answer..

Is this solution Helpfull? Yes | No (2)  

shubham gupta  (9 years ago)

1+0=1 2+0=2 ........... similarly 9+0=9
1+1=2 2+1=3
1+2=3 2+2=4
.
.
.
. 2+7=9
.1+8=9


9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1 = 34 is ri8 answer...

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vishal  (9 years ago)

the ans is 271

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Aditya dhanuka  (9 years ago)

answer will be 126

Is this solution Helpfull? Yes | No (1)  

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