Answer:
79.4 %
Step-by-step explanation:
volume of cylinder : pi×r²×h
attention ! the question gives us the diameters, so for the radius, we need to cut them in half.
Va = pi × (10/2)² × 8 = pi×25×8 = 628.31853... ft³
Vb = pi × (12/2)² × 7 = pi×36×7 = 791.68135... ft³
100% Vb = 791.68135... ft³
1% Vb = 7.9168135... ft³
now, 628.31853... ft³ have been pumped into B.
so, how often does 1% of the volume of B fit into that filled volume ?
628.31853... / 7.9168135... = 79.36507937...% = 79.4%