Posted on 04/12/2011 1:32:09 PM PDT by grundle
Texas Instruments TI-85 says:
48÷2(9+3) = 2
But Texas Instruments TI-86 says:
48÷2(9+3) = 288
I'm not even sure that they teach it in high school or college any more.
Some events of 14 October in History.
In 1066, Normans under William the Conqueror defeat the English at the Battle of Hastings.
In 1912, Theodore Roosevelt, campaigning for the presidency, is shot in the chest in Milwaukee.
In 1944, German Field Marshal Erwin Rommel commits suicide rather than face execution for allegedly conspiring against Adolf Hitler.
In 1947, Air Force test pilot Chuck Yeager broke the sound barrier over Muroc Dry Lake in California.
The Square of 288 is 82944. On August 29, 1944 American Troops marched down the Champs-Elysees after liberating Paris.
The Square Root of 288 is 16.97. On January 6, 1997 Newt Gingrich was reelected as Speaker of the House.
It’s been a long time since I’ve done integrals, but 7168, right?
What many of these people who think the answer is 288 don’t understand is that 2(9+3) = (2x9 +2x3) = (18+6) = (24).
Therefore it is obvious to anyone who knows the fundamentals of solving an equation that the answer must be 2.
They even acknowledge that the parentheses needs to be solved first, but somehow don’t understand or won’t admit that solving the parentheses yields an answer of 24.
They ignore the distributive rule.
If the problem was 48/2 x (9+3), 288 would be the correct solution, but that is not the problem.
Wow, I am really rusty with that calculus stuff. Haven't needed it for more than 25 years.
Wow, I am really rusty with that calculus stuff. Haven't needed it for more than 25 years.
“So, you can’t cite any rule, then? You have the whole wide internet at your disposal.”
It was a joke......seriously, it’s not my job to correct the years of public school mis-education.
Just don’t be the one programing my re-entry vehicle.....
Educate me about the TI a bit. Was a multiply key entered after the 2 digit in this sequence? Is it the practice of these calculators not to show a multiply sign?
In any event, it’s odd that the 85 model would interpret the expression as it did. There’s simply no reason to implicitly group the 2 with the (9+3).
As others have pointed out, the standard way of evaluating this expression is to evaluate parens first, taking care of the (9+3). Then, evaluate multiply and divide at an equal level, going from left to right.
The 85 doesn’t do that, and the 86 does. Clearly, the designers considered that a bug in the 85. I agree.
By the way, my HP35a gives 288. (Yes, the silly thing has an algebraic mode!)
As does C. I know...I know...show your work:
cat c.c
#include <stdio.h>
int main(void)
{
printf("The only answer is: %d\n", 48 / 2 * ( 9 + 3));
return 0;
}
cc c.c -o one_true_way
./one_true_way
The only answer is: 288
Goodnight all, you've been a great crowd!
If the excel spead sheet was not designed properly, you would get an incorrect answer. It problem with such an excel spread sheet is the operator and not the program.
My brother, the family high achiever , who was achieving while I was getting high (I hate him!), double Ph.D, math prof at MIT, as well as at the University of Vienna, and an internationally known authority, told me minutes ago in no uncertain terms not to bother him about such trivial matters, and that it is patently obvious the result equals two hundred eighty eight. So there, end of discussion!
“If the problem was 48/2 x (9+3), 288 would be the correct solution, but that is not the problem.”
48/2 x (9+3)
is the same as
48/2(9+3)
Evaluating operations inside parens takes precedence over the multiplication operation in the distribution, so the next step gives
48/2(9+3) =
48/2(12) =
48/2*12 =
24*12 =
288
288
That is the problem. You ignored commutativity. Factors commute, so 48/2 * (9+3) = 48(9+3)/2 = 288.
Most profound and meaningful thing on this thread so far :^)
48÷2(9+3) =
9+3 = 12 = a
48÷2 = 24 = b
a X b = 288
...
() = 9+3 = 12
left to right -—
48 ÷ 2 = 24
again left to right (total of b X a)
24 X 12 = 288
48/2(9+3)=x
48/2*12=x
48/24=x
2=x
I solved it the same way you did.
The question is 48 divided by what?
“What” is 2 times (the sum of 9 plus 3) or 2 x 12, which is 24. Distributive yields the same answer: 18 plus 6 equals 24.
Otherwise you have mass confusion, as witnessed by this very thread.
“......If the problem was 48/2 x (9+3), 288 would be the correct solution, but that is not the problem.”
You are correct. I think the poster that stated that it may be the difference between the way various generations were taught. Nowadays people rely solely upon calculators, having either never learned or have forgotten any algebra/calculas/trig/geometry classes.......
Notice the 288 crowd always seperates the 2 from the (9+3) without any reason other than to say the / following the 48 should go first.
48/2 * 48/(9 + 3) = 96 is just as valid under their logic.
Hmmmnnnn... You've got me thinking. But, the question comes as to whether we view "2(9+3)" as a single expression in the equation, or not. How would you solve 48/2(a+b)? Do you see 24/(a+b) or do you see 48/(2a+2b)? It's kind of whacky using the "/" sign instead of writing it out the way math should be written. :-)
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