If A = 60° and B = 30°; the value of sin A cos B + cos A sin B is equal to :

1. $\dfrac{1}{2}$

2. 1

3. 2

4. ${\sqrt2}$

sin A cos B + cos A sin B = sin 60°. cos 30° + cos 60°. sin 30°

$= \dfrac{\sqrt3}{2} \times \dfrac{\sqrt3}{2} + \dfrac{1}{2} \times \dfrac{1}{2}\\[1em] = \dfrac{3}{4} + \dfrac{1}{4}\\[1em] = \dfrac{3 + 1}{4} \\[1em] = \dfrac{4}{4} \\[1em] = 1$

Hence, option 2 is the correct option.