Answer:
individual isotopes
Re 185 = 139.094
Re 187 = 232.815
Explanation:Correcting the typo error for natural abundance as 37 40 as 37.40 and 62 60 as 62.60
Answer is found as follows
For Re 185 natural abundance 37.40%
371.9087 x 37.40/100 = 139.0938538
six significant figures after rounding off = 139.094
For Re 187 natural abundance 62.60
371.9087 x 62.60/100 = 232.8148462
six significant figures after rounding off = 232.815