next number of the sequence 6, 21, 24, 84, 861, 2271, ..... will be

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28 Jul 2011 sequence

next number of the sequence
6, 21, 24, 84, 861, 2271, ..... will be

OPtion

1) 4542
2) 2348
3) 2454
4) 3246
5) 4832
6) 1728
7) 1986
8) 3958
9) 5468
10) none of these

Solution

First number is 6
6*2 = 12
reverse of this number is 21
21*2 = 42
reverse of this number is 24
proceed similarly

Correct Option: 3 Best Solution (6)

~Sandeep~   12 years AGO

Sequence is Multiply last number by 2 and reverse digits
6*2=12 => 21
21*2=42 => 24
24*2=48 => 84
Similarly 2271*2 = 4542, Reversing we get 2454

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dharmaveer   12 years AGO

6*2 =12, now reverse the digits to get 21.

similarly,
21*2 = 42, reverse is 24
24*2 = 48, reverse is 84
84*2 = 168, reverse is 861
861*2 = 1722, reverse is 2271
2271*2 = 4542, reverse is 2454

so, option 3

Like? Yes (6) | No (1)  

Dimple   12 years AGO

6*2 =12,
when we reverse the digits, we get 21.

21*2 = 42, reverse it to 24

24*2 = 48, reverse it to 84

84*2 = 168, reverse it to 861

861*2 = 1722, reverse it to 2271

2271*2 = 4542, reverse it to 2454 .. option 3

Like? Yes (8) | No (5)  

Pargat Pal Singh   12 years AGO

6 -> 6
6*2=12
12... change to -> 21
21*2=42
42 -> 24
24*2=48
48 -> 84
84*2=168
168 -> 861
861*2=1722
1722 -> 2271
2271*2=4542
4542 -> 2454

Like? Yes (4) | No (3)  

Aradhana   12 years AGO

6*2=12 bt d 2nd no. in d series is 21(reverse of 12)
21*2=42 bt d 3rd no. in d series is 24 (reverse of 42)
24*2=48 bt d 4th no. in d series is 84 (reverse of 48)
84*2=168 bt d 5th no. in d series is 861 (reverse of 168)
861*2=1722 bt d 6th no. in d series is 2271 (reverse of 1722)
2271*2=4542
similarly, d 7th no. in d series vl b 2454 (reverse of 4542)

ans: 2454(option 3)

Like? Yes (3) | No (2)  

dharmil   12 years AGO

4542.
this series is 2 times previous number,where alternate terms are written in reverse order.
first term is 6.
6*2=12 but it is written in reverse order that is 21.
21*2=42,reverse order is 24.
24*2=48,reverse order is 84.
84*2=168,reverse order is 861.
861*2=1722,reverse order is 2271.
2271*2=4542,reverse order is 2454.

Like? Yes (1) | No (3)