If i've got the distance of the golden gate bridge right ,then it should be 20.88,you can round that up to either 20 or 21
First, find the number of females in the class. 
Then, just write the ratio. 
Answer:
B 8.56
this is the answer because you simply add what he bought so 1.13+1.13+1.76 which is 4.02 then subtract what he started with which was 12.58 so 12.58-4.02 is 8.56 so that's your answer
1 hm=100m
1.5hm=150 meters each tower is from each other.
500km(1000m/1km)=500,000 meters the wire covers.
500,000/150 = 3333.33 towers. Just because we want to be safe and have enough towers we can say we have 3334 towers in the span of 500,000 meters.
B)
1kV=1000V
500kV(1000V/1kV)= 500,000 V
There are 1.2 volts in a AA battery so we divide 500,000/1.2 = 416666.67 times larger
