We love math
- Thread starter arzafar
- Start date
arzafar
Junior Member
sum of arithemtic series = (n/2)[2a + (n-1)d]
1,2,3,4,5,6,.....,k
odd nos (k+1)/2 : 1,3,5,......,k
even nos (k-1)/2 : 2,4,6,....,k-1
sum of even nos from 1 to k = [(k-1)/4][2(2) + {(k-1)/2 - 1}2]
= (k-1)(k+1)/4
= (k^2 - 1)/4
so (k^2 -1) = 4*79*80
k = 159
Muslimz
Allahisenough4me
yep! thats right.Another method is:
The number of terms in this set would be: n=(k-1)/2 (as k is odd)
Last term: k-1 ( and 1st term = 2)
Average would be first term+last term/2 = (2+k-1)/2=(k+1)/2
Also average: sum/no. of terms
=>79*80/((k-1)/2)
=>158*80/(k-1)
=>(k+1)/2=158*80/(k-1)
=>(k-1)(k+1)=158*160
=> k=159
The number of terms in this set would be: n=(k-1)/2 (as k is odd)
Last term: k-1 ( and 1st term = 2)
Average would be first term+last term/2 = (2+k-1)/2=(k+1)/2
Also average: sum/no. of terms
=>79*80/((k-1)/2)
=>158*80/(k-1)
=>(k+1)/2=158*80/(k-1)
=>(k-1)(k+1)=158*160
=> k=159
arzafar
Junior Member
arzafar
Junior Member
T1 + T2 + T3 + T4 + T5 = 50x5 = 250
if all temperatures on each of the 5 days was different, then
T1 = 45
T2 = 46
T3 = 47
T4 = 48
so T5 = 64
and range = 64 - 45 = 19
if days can have the same temperatures, then
T1 = T2 = T3 = T4 = 45
so T5 = 70
and range = 70 - 45 = 25
25 is the correct answer.
Muslimz
Allahisenough4me
Ahem..the 2nd part is rite cuz days can have same tepmrature.
The average of temperatures at noontime from Monday to Friday is 50; the lowest one is 45, what is the possible maximum range of the temperatures?
Average=50
Sum of temperatures=50*5=250
As the min temperature is 45,
max would be 250-(4*45) = 70
=> The range = 70(max)-45(min)
=25
The average of temperatures at noontime from Monday to Friday is 50; the lowest one is 45, what is the possible maximum range of the temperatures?
Average=50
Sum of temperatures=50*5=250
As the min temperature is 45,
max would be 250-(4*45) = 70
=> The range = 70(max)-45(min)
=25
arzafar
Junior Member
yeah that's the correct one
So cooooool
Today I saw the Nat Geo "Live Curious" commercial, and it reminded me of trigonometry problems we used to have; "if this, prove this". I thought you guys would be interested
If you are, you breath.
If you breath, you talk.
If you talk, you ask.
If you ask, you think.
If you think, you search.
If you search, you experience.
If you experience, you learn.
If you learn, you grow.
If you grow, you wish.
If you wish, you find.
If you find, you doubt.
If you doubt, you question.
If you question, you understand.
If you understand, you know.
If you know, you want to know more...
And if you want to know more, you are alive...
Therefore: If you are= you are alive
cooooool lol!
http://www.spotformat.com/tv-commercial/national-geographic-channel-tv-commercial---if--live-curious
Today I saw the Nat Geo "Live Curious" commercial, and it reminded me of trigonometry problems we used to have; "if this, prove this". I thought you guys would be interested
If you are, you breath.
If you breath, you talk.
If you talk, you ask.
If you ask, you think.
If you think, you search.
If you search, you experience.
If you experience, you learn.
If you learn, you grow.
If you grow, you wish.
If you wish, you find.
If you find, you doubt.
If you doubt, you question.
If you question, you understand.
If you understand, you know.
If you know, you want to know more...
And if you want to know more, you are alive...
Therefore: If you are= you are alive
cooooool lol!
http://www.spotformat.com/tv-commercial/national-geographic-channel-tv-commercial---if--live-curious
arzafar
Junior Member
Today I saw the Nat Geo "Live Curious" commercial, and it reminded me of trigonometry problems we used to have; "if this, prove this". I thought you guys would be interested
If you are, you breath.
If you breath, you talk.
If you talk, you ask.
If you ask, you think.
If you think, you search.
If you search, you experience.
If you experience, you learn.
If you learn, you grow.
If you grow, you wish.
If you wish, you find.
If you find, you doubt.
If you doubt, you question.
If you question, you understand.
If you understand, you know.
If you know, you want to know more...
And if you want to know more, you are alive...
Therefore: If you are= you are alive
cooooool lol!
http://www.spotformat.com/tv-commercial/national-geographic-channel-tv-commercial---if--live-curious
that seems to be a variant of the classic saying "Cogito ergo sum". I think, therefore I am
philosophy and math dont mix as well as we might think. off course advanced theoretical math is where philosophy comes in. proof theory, logic, infinity etc. Moreover like philosophy math has it's limits (Incompleteness theorems)
arzafar
Junior Member
the question isnt clear. what happens after the third Q? does the person then choose a box at random?
I'm already rusty at this, but I'm bored...
1. 11,500= 10,000 + 3*500
2. .0625= 1/ 16
I'm assuming that you pick the box after answering the questions. Otherwise... if you choose at the onset. 15 box would remain. And, they'd have to split one box into 2!
3. 50%
4. 16/2 =8 (1st question correctly answered)
8/2= 4 (2nd question correctly answered)
4/2= 2 (3rd question correctly answered)
...I hope there's such a TV game show. I would wan to be a contestant!
*Question: has anybody here taken the GMAT, or will take one? any tips would be appreciated just reminded me because I heard there is a part where you have to decide whether the problem statement is enough to draw a conclusion...
*Also, look down at the thread suggestions. It' all pertains to love. haha!
1. 11,500= 10,000 + 3*500
2. .0625= 1/ 16
I'm assuming that you pick the box after answering the questions. Otherwise... if you choose at the onset. 15 box would remain. And, they'd have to split one box into 2!
3. 50%
4. 16/2 =8 (1st question correctly answered)
8/2= 4 (2nd question correctly answered)
4/2= 2 (3rd question correctly answered)
...I hope there's such a TV game show. I would wan to be a contestant!
*Question: has anybody here taken the GMAT, or will take one? any tips would be appreciated
just reminded me because I heard there is a part where you have to decide whether the problem statement is enough to draw a conclusion...*Also, look down at the thread suggestions. It' all pertains to love. haha!