Maths
posted by Izzy on .
Find a three digit number so that when the digita of the number Are added together the total is one fifth of the product of the digits

if the digits are a,b,c then
5(a+b+c) = abc
c = 5(a+b)/(ab5)
so, ab must be greater than 5,
ab cannot be 6, since then a+b > 5
if ab=7, then 5(8)/2 = 20 > 10
if ab=8, then c = 5(6)/3 = 10 too big
if ab=9, then c=5(6)/4 = not integer
if ab=10, then c=5(7)/5 = 7
257: 2+5+7 = 14 = 2*5*7/5