$A.2\frac{2}{5}+3\frac{1}{3}=2\frac{6}{15}+3\frac{5}{15}=5\frac{11}{15}$     

$B.1\frac{1}{2}+4\frac{5}{7}=1\frac{7}{14}+4\frac{10}{14}=5\frac{17}{14}=6\frac{3}{14}$  

$C.4\frac{1}{6}+\frac{1}{4}+1\frac{1}{3}=4\frac{4}{24}+\frac{6}{24}+1\frac{8}{24}=5\frac{18}{24}=5\frac{3}{4}$  

$D.2\frac{3}{20}+1\frac{1}{5}+1\frac{1}{4}=2\frac{3}{20}+1\frac{4}{20}+1\frac{5}{20}=4\frac{12}{20}=4\frac{3}{5}$  


1) C

2) B

3) A i D

$5\frac{11}{15}+4\frac{3}{5}=5\frac{11}{15}+4\frac{9}{15}=9\frac{20}{15}=10\frac{5}{15}=10\frac{1}{3}$