Question

What is the reciprocal of 2 5/7? * A. 45/7 B.19/7 C.7/19 D.5/19

Answer 1

$2\dfrac{5}{7}=\dfrac{19}{7}$

So the reciprocal is $\dfrac{7}{19}$

Answer 2

$2 \dfrac 5 7 = \dfrac{2 \times 7 + 5}{7} = \dfrac{19}{7}$

The reciprocal of x is 1/x, what you get when you swap numerator and denominator.  So here the reciprocal is

$\dfrac{7}{19}$