A. A repeating decimal is rational. sqrt(49) = 7. Sum is rational.
B. sqrt(44) is not rational. sqrt(5) = 5. Sum is irrational.
C. sqrt(36) = 6 and rational. sqrt(21) is irrational. Sum is irrational.
D. sqrt(64) = 8 and rational. A fraction of integers is rational. Sum is rational.
E. sqrt(6) is irrational. sqrt(9) = 3 and rational. Sum is irrational.
F. sqrt(36) = 6 and rational. sqrt(21) is irrational. Sum is irrational.
Answer: Only A and D are rational.
