$\dfrac{-1}{4} \times \left[\dfrac{2}{5} + \left(\dfrac{-5}{6}\right)\right]$ = ?

1. $\left[\dfrac{-1}{4} \times \dfrac{2}{5}\right] + \left[\dfrac{-1}{4} \times \left(\dfrac{-5}{6}\right)\right]$

2. $\left[\dfrac{-1}{4} \times \dfrac{2}{5}\right] - \left(\dfrac{-5}{6}\right)$

3. $\dfrac{2}{5} + \left(\dfrac{-1}{4}\right) \times \left(\dfrac{-5}{6}\right)$

4. $\left[\dfrac{2}{5} + \left(\dfrac{-5}{6}\right)\right] - \dfrac{1}{4}$

By what rational number should $\dfrac{-5}{24}$ be multiplied to get 10?

1. 12

2. -12

3. 48

4. -48

What should be subtracted from $-\dfrac{7}{8}$ so as to get $\dfrac{5}{12}$?

1. $\dfrac{31}{24}$

2. $\dfrac{8}{5}$

3. $\dfrac{-31}{24}$

4. $\dfrac{-6}{8}$

The sum of two rational numbers is -3. If one of the numbers is $\dfrac{-7}{5}$, then the other number is

1. $\dfrac{-8}{5}$

2. $\dfrac{8}{5}$

3. $\dfrac{-6}{5}$

4. $\dfrac{6}{5}$