Silver contains two isotopes Ag 107 and Ag109 and average atomic weight of silver is 108.5 find percentage abundant of isotopes of silver.

 Answer Key: Ag (107) 25% and Ag (109) 75%

Boron have two isotopes B11 and BA and their relative abundant % are 80% and 20% respectively and average atomic weight of Boron is 10.8 find the value of “A”

 Answer Key:  A= 10