you posted this question twice ...
there are six numbers in the set but we don't count the empty set so 2^6-1=63 numbers
first, take away the million and just do 150*2=300 and then bring back the million
so the answer is 300 million
15/60%=25
@Guest: This is not social media. In case you haven't known, this is a math website.
this is a perfect square pattern. so all we need to find is sqrt144=12 so n=12
1 hr=60 min so 6*60=360 mins
1 hr=3600 sec so 6*3600=21600 secs
Hint: Find a pattern!
This is an aops prealgebra 2 problem.
Also, you posted this question twice.
$\$2.74*3.9 =10.686$$\approx$10.69