Spanner,
The voice in the head was an order, loud and clear.
It said put the engine in gear and run the propeller with the starter.
belbab
Simple math question for dum dums
by JH 103 Replies latest jw friends
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jgnat
Max, I looked at that sentence ten times today, and I didn't see it! Boy, you can be sneaky.
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Farkel
max,
I didn't glance at the posts past that challenge, but I did notice that the last multiplication was x 0!
DOH.
ANYTHING times zero is zero!
I'll look at the other challenges now.
In the meantime, there was a future famous (I think German) mathemetican who was in grade school and the teacher asked all the students to add up all the numbers from 1 to 100. All the kids got the wrong answer. This student, however, thought for a few seconds and scirbbled down a simple line or two and came up with the right answer. What did he figure that they couldn't figure out and how did he do it?
Challenge number two (these are both pretty easy, and are the kinds of questions one sees on the various Mensa tests) is this: A teacher asks his/her students to give the total sum of numbers from 1 to 100 which are evenly divisible by two.
What say you? The only student who got this answer right was in deep doo-doo for contradicting the teacher, yet he was right, and she was wrong. He became another great mathematian and she went into obscurity for stifling his brillliant mind.
Farkel
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SpannerintheWorks
Farkel,
What did he figure that they couldn't figure out and how did he do it?
If you add up 1-9 (45) then this figure can be used to add up all the tens and units from 1-100.
I.E., 45x10=450 (all the units)
Then 45x10x10=4500 (all the tens)
Then the one x 100=100
add them all up and you get 5050.
A teacher asks his/her students to give the total sum of numbers from 1 to 100 which are evenly divisible by two.
Well they are all evenly divisible by two. The total sum of all the numbers being 5050.
Spanner
Edited because I typed a 9 instead of a 10.
Edited by - SpannerintheWorks on 23 January 2003 7:28:5
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Fe2O3Girl
Farkels problem 1+2+3+.................+99+100
100+1=101, 99+2=101, ............., 51+50=101
Hence, 50*101=5050
The answer is 5050
It does not take as long to work out as it does to type the explanation.
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Fe2O3Girl
I have tried it another way and got the same answer, so if I have got it wrong I am going to look very stooopid.
1+2+3........+10=55
11+12+13.......+20= (1+2....+10) + (10*10) = 155
21+22+23......+30= (1+2....+10) + (10*20) = 255
and so on, to
91+92+93.......+100= 955
and 55+155+255.......+955 = 5050
Course, that is in pound sterling, not US dollars. We don't have quarters, see?
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Fe2O3Girl
the total sum of numbers from 1 to 100 which are evenly divisible by two.
I have a suspicion that this requires a different approach, and I have not understood the question, but I am assuming that we are being asked for
2+4+6+8+..........98+100
Using the same approach as the previous problem:
2+100=102, 4+98=102, ............50+52=102
25*102=2550
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Realist
the guy who figured that out was Gauss.
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JH
What formula would you use to add this up?
from 20 up to 78 for example? What formula would you use?
(20+21+22+23........76+77+78)=?
The answer is below
Edited by - jh on 24 January 2003 14:46:10
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JH
Here is the JH answer to the question above
A= lets say the smallest digit which is 20 in this case
B=the largest digit in this case which is 78, so enter A and B in my formula
My formula is:
(B+A) X (B-A)+1
2
78+20 X 78-20+1
2
49 X 59 = 2891 That's the answer to my problem.
So instead of adding the whole thing and it could take you a month, just take the smallest number, call it A, and take the largest number and call it B.
Use the formula and Voila.
JH
Edited by - jh on 24 January 2003 14:44:22