31. The quotient of dividing one number by another is an integer that is two times smaller than one of them and six times larger than the other. Find this quotient.
31. Let the dividend be $a$, and the divisor be $b$, then according to the condition, the quotient is $a: 2$ or $6 b$, i.e., $a: 2 = 6 b$, from which $a = 12 b$ and $a: b = 12$. Therefore, the quotient $a: b$ is 12.