2 5 7 12 19 31 50 __________

a) 81 b) 60 c) 70 d) 84

Question

2 5 7 12 19 31 50 __________

a) 81 b) 60 c) 70 d) 84

larseighner · Answer

Try writing the difference between each term and the one that follows it.

anonymous · Answer

81

anonymous · Answer

here 
7=5+2
12 =7+5
19=12+7
and so on...

larseighner · Answer

That's right.

anonymous · Answer

Adding by last 2 numbers will continue the series? right?

anonymous · Answer

and it applys on all questions like this one?

larseighner · Answer

Right.  You cannot tell where the first two numbers came from, but they give you enough numbers to figure out the following ones.

anonymous · Answer

1 2 2 4 8 32 __________

a)256 b) 629 c) 430 d) 512

anonymous · Answer

but in this one multiplying  the last 2 figures is the right answer.. my question is how we figure out the difrnc of adding or multiplying?

anonymous · Answer

yup

larseighner · Answer

In general you can't.  You have to try out one, and if that doesn't work, try out the other.

anonymous · Answer

and whts the answer of this one?

49 36 25 16 9 4 __________

a) 1 b) 2 c) 3 d) 4

anonymous · Answer

1

anonymous · Answer

how?

anonymous · Answer

all are squares of natural numbers in decreasing order
square of 7 is 49
square of 6 is 36
square of 5 is 25
and so on..

anonymous · Answer

ohhh.. ok i got it..:D