Answer:
24/35, about 69%
Step-by-step explanation:
The data given can be put into a 2-way table (attached). It shows that 0.48 of all calls were answered and resulted in a mortgage application. Altogether, 0.70 of all calls resulted in a mortgage application. Thus the conditional probability of interest is ...
p(spoke to attendant | applied for a mortgage) = p(spoke & applied)/p(applied)
= 0.48/0.70 = 24/35 ≈ 69%