s = "$6,178.50 USD / 22,693.01 AED"
delta = 100.0 #only good to 3 sig figs due to 3.75
h = Hash[*s.delete($,/).split()].invert
h.each {|k, v| h[k] = v.to_f}
puts h["US"]
puts h["AED"]
puts (h["US"] * 3.67).between?( h["AED"] - delta, h["AED"] + delta ) )

6178.5
22693.01
true

Todd