It is given in the question that
Jess has dinner at a restaurant. The dinner bill is B dollars. She pays a 21% tip.
THerefore,
Jess's bill amount without tip is $ B.
Jess's tip amount is 21 % of B or 0.21B
THerefore Jess's total amount is the sum of Jess's bill amount without tip and Jess's tip amount, that is
[tex]= B+0.21 B = 1.21 B[/tex]
Hence, Jess's total amount is 1.21B .