A submarine left Pearl Harbor and traveled east. An aircraft carrier left four hours later traveling 30 mph in an effort to catch up to the submarine. After traveling 8 hours, the aircraft carrier finally caught up to the submarine. What was the submarine’s average speed?
Speed of sub ---- x mph
After 8 hours, at x mph, the sub went 8x miles
after 4 hours, at 30 mph, the carrier went 120 miles
8x = 120
x = .....
I actually messed up my times, should have been:
Speed of sub ---- x mph
time of travel of the sub is 12 hours
time of travel of the carrier is 8 hrs
After 12 hours, at x mph, the sub went 12x miles
after 8 hours, at 30 mph, the carrier went 240 miles
12x = 240
x = 20 mph
You clearly meant to say S = 20 , not S = 2
You also obviously caught my error.
i got this thanks
distance of submarine = distance of aircraft
S.t = S.t
S(8+4) = 30.8
12S =240
S=2 mph
Well, I hope the submarine didn't leave any pearls behind in Pearl Harbor! Anyway, let's do some math here. If the aircraft carrier traveled for 8 hours at a speed of 30 mph, it covered a distance of 8*30 = 240 miles. Since it caught up to the submarine, we know that the submarine also traveled the same distance. So, if the submarine traveled for a total of 8 + 4 = 12 hours, its average speed would be 240/12 = 20 mph. The submarine's average speed was 20 mph.
To find the submarine's average speed, we need to use the formula:
Average Speed = Total Distance / Total Time
Let's break down the information given:
1. The aircraft carrier left four hours later than the submarine.
2. The aircraft carrier traveled for 8 hours before catching up to the submarine.
3. The aircraft carrier traveled at a speed of 30 mph.
Since the submarine already had a head start of four hours, we need to find the total time they both traveled.
Total Time = Time traveled by the aircraft carrier + Time traveled by the submarine
The submarine's travel time is the same as the aircraft carrier's travel time, plus the additional four hours.
So, the submarine's total travel time can be expressed as:
Total Time = Time traveled by the aircraft carrier + 4 hours
Substituting the given values:
Total Time = 8 hours + 4 hours
Total Time = 12 hours
Now we can calculate the total distance by multiplying the aircraft carrier's speed by its travel time:
Total Distance = Speed x Time
Total Distance = 30 mph x 8 hours
Total Distance = 240 miles
With all the required information, we can finally calculate the submarine's average speed:
Average Speed = Total Distance / Total Time
Average Speed = 240 miles / 12 hours
Average Speed = 20 mph
Therefore, the submarine's average speed was 20 mph.