Question 602818
let b be the age of brain
let s be the age of steve
let p be the age of phil
b+s+p=53
b=2(s-5)
s=(b+10)/2
b=p-2
p=b+2
substitute
b+(b+10)/2 +b+2 = 53
2b+b+10+2b+4=106
5b= 92
b=92/5=18.4
s=(b+10)/2=14.2  
p=b+2= 20.4
so the age of the oldest is 20