9,18,21,25,20,?
(IBM Question)
Asked by Saikat
Aparajita   @ Arup chowdhury how?
7 years ago
Shobhit Saxena   @tapas how?
7 years ago
Saptarshi Ghosh   tell me the logic?
7 years ago
shubhi agrawal   its 27,
9+18=27,2+7=9
21+25=46,4+6=10
20+27=47,4+7=11
so it should be 27...
6 years ago
thamaraikannan   i think 21
9+(3*3)=18
21+(2*2)=25
20+(1*1)=21
6 years ago
thamaraikannan   it would be easy if choices are given
6 years ago
Vivek   15
6 years ago
Atul Gupta    10 or 9
20-18=2
25-21=4
hence x-9=1 or x-9=0
x=10 or 9
6 years ago
soujanya   @Vivek how 15???? tell me your logic
6 years ago
Bhumika   ANSWER WILL BE 36
6 years ago
Bhumika   9*2-0=18
9*3-6=21
9*4-11=25
9*5-15=20
9*6-18=36
6 years ago
Jeet Roy   @Bhumika how can 9*5-15 be 20 ?
6 years ago
Lucy Desouza   I think Answer will be 19
Logic: 9,18,21,25,20,?((19))
Ist Difference : 9 ,3,4, -5 ((( -1)))
2nd Difference: -6,1,-9 (((4)))
3rd Difference:7 , -10 ((((13))))--Below for details
Right of -10 the Number will be positive greater than 10 so think it as 13 because Its increased by magnitude three. 7,-10,13.Now move up the order to get 19
6 years ago
Anand Kumar   40
6 years ago
chirag    I thing answer will be 55

Explanation:

9, 18, 21, 25, 20, ?
1, 2, 3, 4, 5, 6 ---------->position no
On the basis of combination of their position
Taking
(1,3)=1st combination
(2,5)= 2nd combination
(4,6)= 3rd combination
in 1st :
9=3*3
21=3*7
In 2nd:
18=2*9
20=2*10
In 3rd:
25=5*5
x= 5*y
3rd combination are following the pattern same as 1st combination
Prime no1*prime no1
Prime no1*prime no 2

If we following this pattern y will be 11(in 1st patter equation taking 7 as prime no2 not to 5, so i m taking 11 as another prime no)

5*5=25
5*11=55
6 years ago
kamlesh meher   9*2-0=18
9*3-6=21
9*4-11=25
9*5-15=20
9*6-18=36
6 years ago
Amit Kumar   9*5-15=30 not 20 wrong logic
6 years ago
shubhra gupta   i think it is a wrong question...
6 years ago
Amarjeet Kumar   for this type of series.. we will divide series in two part..
9,18, 21 and 25,20,---.
3*3=9 (3*1=3)
3*6=18 (3*2=6)
3*7=21 (3*2+1=7)
next...just reverse order..
5*5=25 (2*2+1=5)
5*4=20 (2*2=4)
5*2=10 (2*1=2)

so Ans is "10"
5 years ago
santosh kumar sahu   yes u are ri8tttt
5 years ago
bikesh   16
5 years ago
s janani   answer is 21
take the numbers in positions 1,3 and 5
9+3^2=18
21+2^2=25
20+1^2=21
5 years ago
ABHAY   10
3 years ago
Madhavi   10
3 years ago
Abhigyan   Answer is 14. My calculation is
9 *(1)=9
9 *(2)=18
18+(3)=21
21+(4)=25
25-(5)=20
20-(6)=14
2 years ago

Smiley