a/(a+b) = 37/40
(a+b)/a = 40/37
a/a + b/a = 40/37
1 + b/a = 40/37
b/a = 40/37 - 1
= 3/37
1 - b/a = 34/37
(a-b)/a = 34/37
a/(a-b) = 37/34
Good Luck
