Question 182721
Alfred is twice as old as his brother. Four years ago he was four times as old. How old is Alfred now?

:
lets call the ages of alfred and brother, a and b , respectively
:
a=2b.......eq 1
a-4=4(b-4).eq 2
:
take a's value of 2b from eq 1 and plug it into eq 2
:
2b-4=4(b-4)
:
2b-4=4b-16
:
2b=12
:
{{{highlight(b=6)}}}age of brother
:
{{{highlight(a=2(6)=12)}}}age of alfred