Answer
$P(less$ $than$ $45)=\frac{6322}{6427}\approx0.984$
If we randomly select 1000 mothers involved in a multiple birth we would expect about 984 to be mother who was less than 45 years old.
Work Step by Step
N(S) = 6427 and N(45-54) = 105. So:
$P(45-54)=\frac{N(45-54)}{N(S)}=\frac{105}{6427}$
The event "mother who was less than 45 years old involved in a multiple birth" is the complement of "mother 45 to 54 years old involved in a multiple birth". So:
$P(less$ $than$ $45)=1-\frac{105}{6427}=\frac{6427}{6427}-\frac{105}{6427}=\frac{6322}{6427}\approx0.984$
