#28, 18, 10, ?#

3 Answers
mathexpert
Oct 19, 2017

The pattern is 28,18,10. You can see that it decreases by 10 from the1st term to the 2nd term. Then it decreases by 8 from the 2nd term to the 3rd term. The number that each term decreases by decreaaes by two. So the difference between the 3rd term and 4th term is 6. 10-6=4. So the next term is 4.

David Drayer
Oct 19, 2017

This looks like a function where the value decreases by n-2, the next numbers in the sequence would be 4

Explanation:

# 28 -18 = 10# where n-2 = 10
# 18 -10 = 8 # where n-2 = 8 ( 10-2)
# 10 -4 = 6 # where n -2 =6 ( 8-2)

So the sequence would be 28, 18, 10, 4

Alan N.
Oct 19, 2017

I'll go with 4

Explanation:

Since we only have 3 elements of the sequence, I expect there are several solutions to this problem.

Nevertheless, I'll justify 4 as follows:

All given elements are even, so let's assume that the next element is even too.

That means we can write the sequence as:

#2(14, 9, 5, ?)#

Then the differences between adjecent elements in the parenthese are (-5, -4) so, the next difference would be #-3#

Then #5-3=2#

So, our rewritten sequence would be:

#2(14,9,5,2)#

In original form:

#28, 18, 10, 4#

NB: I'd be intrested to see other solutions.

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