boron exist as two isotopes ^{10}B and ^{11}B if atomic mass of boron in periodic table is given to 10.81 what is the relative abundance of the heaver isotop?

Q. Boron has two isotopes, ${}^{10}B$ and ${}^{11}B$ whose relative abundances are $20$% and $80$% respectively. Atomic weight of boron is:

Q. Boron has two stable isotopes, ${}^{10}B\left(19\text{\%}\right)$ and ${}^{11}B\left(81\%\right)$. Calculate average atomic mass of boron in the periodic table.

Q. Atomic mass of boron is 10.81. It has two isotopes namely ${}_5^{11}B$ and ${}_5^{x}B$ with their relative abundance of 80% and 20% respectively. The value of x is:

Q. Atomic mass of boron is 10.81. It has two isotopes with 80% and 20% abundance respectively. The atomic mass of the isotope having 80% abundance is 11.01. The atomic mass of the other isotope is: