i'm not smarter than a 3rd grader [homework help]

Another ridiculous longshot:

12 + 3 * 1 (1 is the first digit in 12) = 15
15 + 4 * 1 = 19
19 + 5 * 1 = 24
24 + 6 * 2 (2 is the first digit in 24) = 36
36 + 7 * 3 (3 is the first digit in 36) = 57
57 + 8 * 5 (5 is the first digit in 57) = 97
97 + 9 * 9 = 178

 

It's quite obvious that it isn't a typo, but rather that the #30 is missing. I would insert a carrot on the question and include 30.

Then it is 12, 15, 19, 24, 30, 36, 43, 51, etc.

 

+3
+4
+5
+6
+6?
+7
+8

huh

 

That wouldn't be correct because:
24 + 6 = 30
30 + 7 = 37 (not 36)

I agree that the 36 is a typo.

 

12, 15, 19, 24, 30, 37, 45, 54

 

oops. Yeah, I meant 37, and so on.

 

but if it is 37, there is a typo.

 

I get: 12, 15 19, 24, 36, 45, 57, 72

because...

12 x 3 = 36 (5th in the series)
15 X 3 = 45 (6th and first blank in the series)
19 X 3 = 57 (7th and second blank in the series)
24 x 3 = 72 (8th and final blank in the series)

 

But there's only one instance of that occuring, not enough to establish a pattern.

 

This is the most correct one I have seen in the whole thread. 3+4+5=12 so the big jump on the 5th number. So after 78, the next number should be 78+(13+14+15) which equals 120

 

Yeah that's wack, it's a typo plain and simple.

Theres no way third graders are supposed to figure out stuff THAT hard, if you fix the typo its a legitimate series.

http://www.research.att.com/~njas/sequences/A017903

There you go, also wasn't that homework due by now?

 

I've got to go with professorjay, the answer is 12, 15, 19, 24, 36, 57, 97, 178.
I came up with the same answer but with a different formula. Here is a formula that does it:

<pre>
pseudocode:
x=12
for n in 1 to 8
x = x + (n+2)*floor(2^(n-1)/n)

perl code:
use POSIX qw(floor);
my $x = 12;
for my $n (1..8) {
print $x."\n";
$x = $x + (($n+2) * floor(2**($n-1)/$n));
}
</per>

 

psh that's a bit simple for third grade, huh? we're supposed to be challenging kids today, not giving them remedial perl.

 

It works mathematically. It fits. It could be anything that meets those criteria. The pattern was established and repeated three times.

 

Seems the most logical answer, as a typo would still not fit. It's not really a sequence though, and for that reason it didn't make sense to me upon first inspection.

Seriously, this stuff can't really be 3rd grader stuff. I'm excellent at math, and this isn't intuitively obvious playing around a bit.

 

LOL. i hope that's the answer the teacher is expecting, and also the explanation. 3rd grade should be the new 12th grade.

 

I don't know about you, but I never did that in the 12th grade.

 

You're smarter for going to the bbs you mean