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A truck driver drove for two days. On the second day she drove 2 hour

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Math Expert
Joined: 02 Sep 2009
Posts: 58427
A truck driver drove for two days. On the second day she drove 2 hour  [#permalink]

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06 Jan 2018, 08:14
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Difficulty:

25% (medium)

Question Stats:

75% (02:36) correct 25% (02:44) wrong based on 74 sessions

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A truck driver drove for two days. On the second day she drove 2 hours less and at an average speed 5 miles per hour faster than she drove on the first day. If during the two days she drove a total of 1,245 miles and spent a total of 20 hours driving, what was her average speed on the first day?

A. 55 mph
B. 58 mph
C. 60 mph
D. 62 mph
E. 65 mph

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Joined: 30 May 2017
Posts: 36
GMAT 1: 730 Q49 V41
Re: A truck driver drove for two days. On the second day she drove 2 hour  [#permalink]

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06 Jan 2018, 08:34
A truck driver drove for two days. On the second day she drove 2 hours less and at an average speed 5 miles per hour faster than she drove on the first day. If during the two days she drove a total of 1,245 miles and spent a total of 20 hours driving, what was her average speed on the first day?

A. 55 mph
B. 58 mph
C. 60 mph
D. 62 mph
E. 65 mph

Let x be the no. of hrs truck driver drove on first day and Y be on second day.

X+Y=20
X-Y=2

therefore x=11 and y=9
Now Let s be speed on 1st day
S=D/11----1
on second day,

S+5=1245-D/9----------2

from 1 and 2 S=60

Let me know if there's a flaw
Math Expert
Joined: 02 Aug 2009
Posts: 8006
Re: A truck driver drove for two days. On the second day she drove 2 hour  [#permalink]

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06 Jan 2018, 08:46
Bunuel wrote:
A truck driver drove for two days. On the second day she drove 2 hours less and at an average speed 5 miles per hour faster than she drove on the first day. If during the two days she drove a total of 1,245 miles and spent a total of 20 hours driving, what was her average speed on the first day?

A. 55 mph
B. 58 mph
C. 60 mph
D. 62 mph
E. 65 mph

TIME
If she drove for x hours on first day, she traveled x-2 on second day, so $$x+x-2=20...x=11$$
hour traveled on first day = 11 and on second day 9

DISTANCE
if on first day average speed was y, on second day it was y+5..
so $$11y + 9(y+5) = 1245....9y+11y+45 = 1245....20y=1245-45=1200...y= 60..$$

C
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A truck driver drove for two days. On the second day she drove 2 hour  [#permalink]

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06 Jan 2018, 08:51
Bunuel wrote:
A truck driver drove for two days. On the second day she drove 2 hours less and at an average speed 5 miles per hour faster than she drove on the first day. If during the two days she drove a total of 1,245 miles and spent a total of 20 hours driving, what was her average speed on the first day?

A. 55 mph
B. 58 mph
C. 60 mph
D. 62 mph
E. 65 mph

Let x = average speed Day 1
x + 5 = average speed Day 2
Solve for time, then distance.

Total time 20 hours, 2 hrs less on Day 2 = (t-2)
t + t - 2 = 20
2t = 22
t = 11: Day 1
t - 2 = 9: Day 2

Distance, rt = D
Day 1: x * 11 = (11x)
Day 2: (x + 5) * 9 = (9x + 45)
Day1 + Day 2 = total distance
11x + 9x + 45 = 1,245
20x = 1,200
x = 60

Average speed Day 1 = 60

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A truck driver drove for two days. On the second day she drove 2 hour   [#permalink] 06 Jan 2018, 08:51
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