Maths Problem!!! (1 Viewer)

[lookoutastroboy]

Hi peeps,

Just one small question, from AMC - Problem: 2000 = 2^4 x 5^3 is the product of 7 prime factors. X = smallest integer greater than 2000 with his property and y be the largest integer smaller than 2000 with this property. Value of x - y?








Ciao, Timemagazine Express

 

[Azreil]

2000 = 2 * 2 * 2 * 2 * 5 * 5 * 5
3000 = 2 * 2 * 2 * 3 * 5 * 5 * 5
1200 = 2 * 2 * 2 * 2 * 3 * 5 * 5

So x - y = 1800
Is that what the answer was? That was just a guess, mind you.

 

[Timothy.Siu]

2000 = 2 * 2 * 2 * 2 * 5 * 5 * 5
3000 = 2 * 2 * 2 * 3 * 5 * 5 * 5
1200 = 2 * 2 * 2 * 2 * 3 * 5 * 5

So x - y = 1800
Is that what the answer was? That was just a guess, mind you.

no...not even close.
and a pretty stupid guess. u didn't even put any effort into the question

 

[syriangabsta]

what...could a q like this come into the hsc?

this isnt maths, its annoying!

 

[tommykins]

what...could a q like this come into the hsc?

this isnt maths, its annoying!

i don't believe it would be.

 

[PC]

The largest integer smaller than 2000 with 7 prime factors is 1984.
1984 = 2 x 2 x 2 x 2 x 2 x 2 x 31

The smallest integer greater than 2000 with 7 prime factors is 2080.
2080 = 2 x 2 x 2 x 2 x 2 x 5 x 13

So the difference is 2080 – 1984 = 96.

I used the "brute force" method. Is there a trick?

Which AMC did this come from? It wasn't in this year's paper.

 

[Timothy.Siu]

i love brute force method

 

[Azreil]

no...not even close.
and a pretty stupid guess. u didn't even put any effort into the question

And your answer had so much effort put into it, I can tell. Well done for insulting someone on a maths forum :]

Perhaps you were meant to assume the first 4 factors were 2? And find the product of three primes closest to 125?

 

[trailblazer]

The largest integer smaller than 2000 with 7 prime factors is 1984.
1984 = 2 x 2 x 2 x 2 x 2 x 2 x 31

The smallest integer greater than 2000 with 7 prime factors is 2080.
2080 = 2 x 2 x 2 x 2 x 2 x 5 x 13

So the difference is 2080 – 1984 = 96.

I used the "brute force" method. Is there a trick?

Which AMC did this come from? It wasn't in this year's paper.

There is always a trick.

 

[syriangabsta]

waste of time imo...we got 2 days till english!!!

thi is worth what, 2mrks?