The keyword is "sum" which tells you x, y, and z are being added. One half of the sum means that the sum of the three numbers is going to be divided by 2.
x + y + z
------------
2
Multiplication because you are going to multiply the recipe by 2 to double it.
So first calculate the time between the plane flied over the Air Force Bases (AFB) and Navy Base Station (NBS):
(time passed Air Force Bases) - (time passed Air Force Bases) = 10:32 - 10:20 = 12 mins
Since we know the distance that plane travel from AFB to NBS is 120 miles and the plane traveled that distance within 12 minutes.
We have
120 miles / 12 minutes = 10 miles / minute
Calculate it into miles per hour (60 minutes):
10 miles/minute x 60 minutes = 600 miles per hour.
ANSWER : 600 mph
If you want to increase something by 3%, you would ADD 100% to it, so:
3% + 100% = 103%
Then you divide it by 100 to turn it into a decimal, so:
103% / 100 = 1.03
So to increase by 3%, the multiplier would be 1.03
If you wanted to decrease by 3%, you would SUBTRACT 100% from 3%, so:
100% - 3% = 97%
And then you would divide 97% by 100 to turn it into a decimal (multiplier), so:
97% / 100 = 0.97
So to decrease by 3%, the multiplier would be 0.97
