Update RateConverter.java

Is this a good way? Anyway I still can't pass the first test in RateConverterTest
in your test you have 2 SAP at 85 euro each, totaling 170 euro

In implementation I find the euro at 1.35 and I multiply it for the number of shares we have, making 2.7.

What I don't get it's how do I find, in the body of method "convert", the value 85 for a SAP share?
Thanks