Thread: Question

Three numbers p, q and r are all prime numbers less than 50 with the property that . How many values of r are possible?

I would think this is 0 because prime numbers have to be odd and odd + odd always equals an even number. But the answer is not 0

It's not all prime numbers odd. You forget 2 which is prime and even.
Then if p=2 and q=3 then p+q=2+3=5=r and p,q,r are all primes.
Same if p=2 and q=5 then r=7.
Check if there are any more...

wow forgot about 2...

ok

2,3
2,5
2,11
2,17
2,29
2,41

did i miss any?

OK I have another one.

When 1000^2008 is written as a numeral, the number of digits written is..

How do you go about doing this?

I don't quite understand what you want for the last one you asked
You want to know how many digits this number has?? Too many!

1000^1 = 1000 ( 4 digits)

1000^2 = 1,000,000 (7 digits)

1000^3 = 1,000,000,000 (10 digits)

there is pattern ^^

oo alright! so if has 7 digits (6 zeros) that means



(the extra 1) is 6025!