Steam boat (b) = speed of 36.8km/h. In 1.75 hours out same port and going same direction departed speed boat (s). In 1.8 hours later distance between the speed boat (s) and steam boat (b) was 86.9km
Scenario A) the steam boat (b) stays ahead of the speed boat (s)
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Start by first finding the total distance (d) that the steam boat (b) traveled. That would be 1.75+1.8 = 3.55 hrs
distance (d) = rate (r) × time (t)
d(s) = rt = (36.8km/h)(3.55h) = 130.64 km
Secondly, let's subtract from d the distance between b and speed boat (s):
d(s) = 130.64 - 86.9km = 43.74 km
Thirdly, since s traveled 43.74 km and left 1.8 hrs ago, let's set-up the rate of b [r(b)] equal to that distance [d(s)] divided by the time 1.8 hrs.
**Since d = rt, r = d/t
r(s) = d(s)/t = 43.74km/1.8h = 24.3km/h
Scenario B) the speed boat (s) moves ahead of the steam boat (b), this is more likely!!
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b moves before s starts for 1.75 hrs, going 36.8km/h, that distance ahead + distance it travels after the next 1.8 hrs = 130.64 km
Now s starts and travels d(s) km at r(s) km/h
If s speeds past b in 1.8 hrs, and is AHEAD by the given distance of 86.9km, then total distance of s [d(s)] = the 130.64 b traveled PLUS the 86.9 it is now ahead
d(s) = 130.64+86.9 = 217.54 km
s still only traveled that in 1.8 hrs, so the speed/rate of s is:
r(s) = d(s)/t = 217.54km/1.8h = 120.86km/h
** I think that makes more sense, that a speed boat would move MUCH faster than a steam boat, if 120.9... than over 3 times faster!!
Answer:
252
Step-by-step explanation:
9 x 20 = 180
9 x 28 = 252
Perctange is based on the total number. in this case you don't know it so you cant make such a guess.
Answer:
It'll take 12 minutes to be at 30 degrees.
Step-by-step explanation:
Since the metal is cooling at a linear rate then the rate of degrees per minute should be the through the cooling process. From 4 minutes to 7 minutes there was a span of 3 minutes and in that time the metal cooled 105 degrees. So the metal is cooling at a rate of
rate = 105/3 degrees/minute = 35 degrees/min
To reach 30 degrees from 205 it should cool down an additional 175 degrees so it'll take:
minutes = deegrees/rate = 175/(35) = 5 minutes
Since the metal had a temperature of 205 degrees in 7 minutes, then it'll take 12 minutes to be at 30 degrees.
I think the answer is 0.04 try using a calculator
