Question 203929
{{{Area = ((a+b)/2)*h)}}}
{{{1400 = ((a+b)/2)*50)}}}
{{{1400*2/50 = a+b }}}
{{{56 = a+b}}} so far so good.

You are told that both a and b are divisible by 8, so let the possible set of lengths for a and b are [8,16,24,32,40,48]

Now you just need to pair things up
8,48
16,40
24,32
32,24
40,16
48,8