Since Mrs. Thorpe saved $300 per month, and each year has 12 motnhs, we can find the amount of money she saved in a year like this:
12*$300=$3600
Now we know that se saved $3600 each year, to find the amount saved for the 24 years, we simply do:
$3600*24=$86400
And that is the total amount of money she saved. We are told that she spent 40% of the money on a vacation, we can find this amount of money like this:
Now, if we want to find the amount of money that left after the vacations, we just have to subtract the money spent from the initial amount of money:
$86400-$34560=$ 51840
Then the money Mrs. Thorpe has after her vacations is $51840