ANSWERS:
1.clearly the given sequence follows the pattern:
+5,+7,+9....i.e,7+5=12,12+7=19,...
missing no=19+9=28 (b)
2.the patteren is -1,-2,...
missing no is=17-3=14 (c)
3.clearly,the given series is 1^3-1,2^3-2,3^3-3,...
the no occured in last place is 7^3-7=336 (c)
4.the sequence is a combination of two series:
4,12,28,(...) and 6,14,30
now the pattern followed in each of the above series:
+8,+16,+32,....
so,the missing no=(28+32) (b)
5.the sequence is a combination of two series:
1,3,7,?,21 and 3,6,9,12
the pattern followed in 1st series is +2,+4,...;and in 2nd is +3
hence missing no is=7+6=13 (d)
6.the patteren is:+8,+8,+16,+16,+24,..
hence missing no is=73+24=97 (a)
7.the numbers are 1^2-1,2^2-2,3^2-1,4^2-2,.......
missing no is=5^2-1=24 (a)
8.the pattern is +1,+4,+9,+16....i.e ,+1^2,+2^2,+3^2,+4^2,....
missing no is=34+5^2=34+25=59 (d)
9.the pattern is +4,+8,+16,+32....i.e ,+2^2,+2^3,+2^4,+2^5,..
missing no is=81+2^6=81+64=145 (a)
10.the sum of 3 consequtive series terms of series gives the next term is
thus,1+3+4=8;3+4+8=15;4+8+15=27 and so on
the answer is :8+15+27=50 (c)
11.clearly,90=30*3,180=6*30,12=2*6,50=25*2,100=4*25,200=50*4
hence the missing no is:3*50=150 (a)
12.each term in the series is one less than square of the preceding term
thus,2^2-1=3,3^2-1=8,8^2-1=63
missing term is:(63)^2-1=3969-1=3968 (d)
13.the pattern is *2+1,*2-1,*2+1,*2-1,...
missing no is:37*2+1=75 (b)
14.the numbers are 2^2+1,4^2+1,6^2+1,8^2+1,...,12^2+1
missing no is=10^2+1=101 (d)
15.the pattern is +11,+33,+55,..i.e,+(11*1),+(11*3),+(11*5),..
missing no is :104+(11*7)=181 (d)
16.each term in the series is the sum of preceding 2 terms
missing term is:20+31=51 (b)
17.the pattern is *3-1,*3-2,*3-3,*3-4,...
missing term is:(185*3)-5=550 (a)
18.the pattern is /5,/4,/3/2,...
missing no:7/1=7 (b)
19.the sequence is a combination of two series:
1,3,6,10,(..) and 1,9,36,100,225
the pattern in 1st series is +2,+3,+4,..
the numbers in 2nd series are squares of the corresponding numbers of 1
missing no is: 10+5=15 (a)
20.the series is in the format:1^3,2^3,3^3,4^3,5^3,...
hence the next no obtained is:6^3=216 (a)
21.the given sequence consists of pairs of consecutive prime numbers (c)
22.the difference between consecutive terms of the given series are5,7,9,11 and 13
hence,34 is wrong & replaced by (24+11)=35 (c)
23.each term in the series is less than twice the preceding term by 2
so,48 is wrong it should be replaced by (26*2-2)i.e,50 (b)
24.the correct sequence is 3,3^2,3^3,4,4^2,4^3,5,5^2,5^3
so,10 is wrong & must replaced by 3^2 i.e,9 (c)
25.the correct sequence is:+6,+8,+10,+12,+14
so,45 is wrong & must replaced by (30+10)=40 (b)
