The natural boron is composed of two isotopes `._5beta^10` and `._5beta^11` having masses `10.003 u` and `11.009 u` resp. Find the relative abudance of each isotope in the natural boron if atomic mass of natural boron is 10.81u.

The natural lithium is composed of two isotopes of ""_(3)Li^(6) and ""_(3)Li^(7) . The isotopes have masses 6.015121 amu and 7.016003 amu, respectively. Calculate the relative abundance of each isotope in the natural lithium if the atomic mass of natural lithium is 6.94 amu.

The element bron occurs in nature as two isotopes havein atomic masses 10 u and 11 u . What are the percentage abundances of these isotopes in a sample of boron having average atomic mass of 10.8 u?

Natural boron is a mixture of two isotopes ""_(5)B^(10) and ""_(5)B^(11) of masses 10.003 amu and 11.009 amu, respectively. Calculate the atomic mass of natural boron if the relative abundance of ""_(5)B^(10) and ""_(5)B^(11) is 19.97% and 80.03%, respectively.

Naturally occuring boron has two isotopes of masses 10 amu and 11 amu. Calculate the percentage of each isotope if the average atomic mass of boron is 10.2 .

Natural Chlorine is found to be a mixutre of two isotopes of masses 34.98 a.m.u and 36.98 a.m.u. respectively. Their relative abundances are 75.4 and 24.6% respectively. Find the composite atomic mass of natural chlorine.