mathhss :D (1 Viewer)

[super.muppy]

Janes age is a prime number. Andy's age has 8 factors and he is one year older than jane. Of the following numbers could be ths sum of their ages... 27 39 75 87 107
plz explain ur answer

this question is from 2007 westpac maths comp for yeasr 11 and 12 so if anyone has answers to this post it up plz

 

[lychnobity]

Janes age is a prime number. Andy's age has 8 factors and he is one year older than jane. Of the following numbers could be ths sum of their ages... 27 39 75 87 107
plz explain ur answer

this question is from 2007 westpac maths comp for yeasr 11 and 12 so if anyone has answers to this post it up plz

Andy's age = Jane +1

let jane's age be x

x + (x+1) = 27, 39, 75, 87, 107

2x +1 = 27, 39, 75, 87, 107

ie 2 consecutive numbers, the even one must have 8 factors (as the odd one would be the prime)

For 27, 14 clearly is too small to have 8 factors

Same goes for 39, 75, and 87 (respectively these numbers would be 20, 38 and 44)

Leaving the sum of 107, therefore the 2 numbers are 53 and 54

54 has factors 1,2,3,6,9,18, 27 and 54

.'. 107 is the answer

 

[kurt.physics]

Janes age is a prime number. Andy's age has 8 factors and he is one year older than jane. Of the following numbers could be ths sum of their ages... 27 39 75 87 107
plz explain ur answer

this question is from 2007 westpac maths comp for yeasr 11 and 12 so if anyone has answers to this post it up plz

http://community.boredofstudies.org...australian-maths-competition.html#post4478728

This has all the worked solutions to the 2007 papers. And also on posts above the one in the link there is the papers from 2002-2006. The 2008 papers are a bit down the same page =)