A canoeist spent two days on a large lake. On the second day

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A canoeist spent two days on a large lake. On the second day, the canoeist rowed 2 hours longer and at an average speed 2 miles per hour faster than he rowed on the first day. If the canoeist traveled a total of 50 miles and spent a total of 12 hours rowing on his trip, what was his average speed on the first day?

a) 2mph
b) 3mph
c) 4mph
d) 5mph
e) 6mph

Please assist with above problem.
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by GMATGuruNY » Mon Oct 17, 2016 11:54 pm
alanforde800Maximus wrote:A canoeist spent two days on a large lake. On the second day, the canoeist rowed 2 hours longer and at an average speed 2 miles per hour faster than he rowed on the first day. If the canoeist traveled a total of 50 miles and spent a total of 12 hours rowing on his trip, what was his average speed on the first day?

a) 2mph
b) 3mph
c) 4mph
d) 5mph
e) 6mph
Let t = the time on the first day.
Since the time on the second day is 2 hours longer, the time on the second day = t+2.
Since the total time over the 2 days is 12 hours, we get:
t + (t+2) = 12
2t = 10
t = 5.
Thus, the time on the first day = 5 hours, while the time on the second day = 7 hours.

Let r = the rate on the first day.
Since the rate on the second day is 2 hours longer, the rate on the second day = r+2.
Thus:
Distance traveled on the first day = (rate on the first day)(time on the first day) = (r)(5) = 5r.
Distance traveled on the second day = (rate on the second day)(time on the second day) = (r+2)(7) = 7r + 14.
Since the total distance traveled over the 2 days is 50 miles, we get:
5r + (7r+14) = 50
12r = 36
r = 3.

The correct answer is B.
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by Scott@TargetTestPrep » Wed Oct 19, 2016 4:50 am
alanforde800Maximus wrote:A canoeist spent two days on a large lake. On the second day, the canoeist rowed 2 hours longer and at an average speed 2 miles per hour faster than he rowed on the first day. If the canoeist traveled a total of 50 miles and spent a total of 12 hours rowing on his trip, what was his average speed on the first day?

a) 2mph
b) 3mph
c) 4mph
d) 5mph
e) 6mph
We are given that on a second day the canoeist rowed 2 hours longer and at an average speed 2 miles per hour faster than he rowed on the first day.

If we let the number of hours the canoeist rowed on the first day = t, then the number of hours that he canoeist rowed on the second day = t + 2. Also, if we let the rate of the canoeist on the first day = r, then the rate of the canoeist on the second day is r + 2.

Since we are given that the total time spent rowing was 12 hours, we can determine a value for t.

t + t + 2 = 12

2t = 10

t = 5

Thus, 5 hours was spent rowing on day one, and 7 hours on day 2.

We are also given that the canoeist traveled a total of 50 miles. Since distance = rate x time, we can represent the distance traveled on day one as 5r and the distance traveled on day two as 7(r+2) = 7r + 14. Thus:

5r + 7r + 14 = 50

12r = 36

r = 3

Answer: B

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by [email protected] » Wed Oct 19, 2016 10:25 am
Hi alanforde800Maximus,

Certain versions of this prompt will require lots of 'math steps' to get to the solution, but this specific prompt can be solved with a bit of logic and just a little math.

To start, we're told that the TOTAL trip was 50 miles and took 12 hours. That's an average of 50/12 = 4 1/6 miles/hour.

We're told that the two speeds differed by 2 miles/hour, and we spent just 2 extra hours at the faster speed. Thus, the slower speed was measurably below 4 1/6 mph and the upper speed was measurably above 4 1/6 mph. Remember - the speeds DIFFER by 2mph. We're asked for the speed on the first day (re: the slower speed). Looking at the answer choices, we can quickly compare what each answer implies to what the math dictates must happen...

Answer A: slow speed = 2mph, fast speed = 4mph. Does not make sense (the faster speed has to be GREATER than 4mph).
Answer B: slow speed = 3mph, fast speed = 5mph. This matches the logic really nicely.
Answer C: slow speed = 4mph, fast speed = 6mph. Here, the slow speed is just barely below the average speed, which doesn't make sense.

The remaining two answers will just get further and further away from the average, so we don't have to think much about them.

Final Answer: B

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by fiza gupta » Thu Oct 20, 2016 5:19 am
let first day travelled t time
2nd day travelled 2 hours more = t + 2
total time : T+t+2 = 12
t = 5 , second day = 7

speed be s for first day
second day = s+2
distance travelled first day = d = (s*5)
distance travelled second day = d = (s+2)*7
total distance = 50
5s+(s+2)*7 = 50
12s = 36
s = 3
SO B
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by Matt@VeritasPrep » Fri Oct 28, 2016 12:17 am
First Day's D + Second Day's D = 50

First Day's RT + First Day's RT = 50

R*T + (R+2)*(T+2) = 50

We're told that T + (T + 2) = 12, so T = 5. Plugging that into our first equation, we have

5*R + 7*(R + 2) = 50

so R = 3.