If 5a + 2b5a − 2b=53, then a : b =
5a + 2b5a − 2b=53
5a + 2b + 5a − 2b5a + 2b − 5a + 2b=5 + 35 − 3 [Applying componendo and dividendo]
10a4b=82
2(5a)2(2b)=82
ab=85