\(\frac{9}{13}\)
\(\frac{9}{5}\)
5
\(9\frac{3}{5}\)
Correct answer is D
\(\frac{3}{4}t+\frac{1}{3}(21-t) = 11; \frac{3t}{4} + \frac{7}{1} - \frac{t}{3} = \frac{11}{1}\\
\frac{3 \times 3t + 7\times 12 – 4 \times t = 11 \times 12}{12}\\
9t + 84 – 4t = 132; 5t = 132 – 84\\
5t = 48; t = \frac{48}{5} = 9\frac{3}{5}\)