DID I DO THIS RIGHTT...PLEASE ANSWER!! NOONE IS HELPING ME!?

Question

Did i do this correctly?????

on a weekend trip, you average 35 mph in the city and 60mph on the highway. if the 150 mile trip took 3 hours how much of the time were you driving in the city? I DID THIS ALREADY AND MY ANSWER WAS 1 HOUR..IS THAT RIGHT??

i did 35+60 =95 so then 150-95=55 then i was like okay if the highway took 60mph and it was 55 left then it would just go to the highway so only 1 hour was spent on the city. RIGHT OR WRONG??

I DIDNT DO THIS ONE...BECAUSE I DONT KNOW HOW..HELP?

and on august 15th 1995 the concorde flew 35,035 miles from new york city to new york city in 31 hours 27 minutes. what was the average speed?

Answer 1

First problem:

city rate = 35

highway rate = 60

total distance = 150 miles

time = 3 hours

city time = x

highway time = 3-x

RT = D

RT of city + RT of highway = total distance

35(x) + 60(3-x) = 150

35x + 180 - 60x = 150

-25x + 180 = 150

-25x = -30

x = 30/25

x = 6/5

city = 6/5 of an hour = 1 hour and 12 minutes

Second problem:

RT = D

R = ?

T = 31.45 hours

D = 35,035

R(31.45) = 35,035

R = 35,035/31.45

R = approximately 1114 mi/h

Answer 2

No, I'm afraid you did not do it correctly, but at least you tried, and

that's more than a lot of students do.

If you spent 1 hour in the city, as you concluded, then you must have

spent 2 hours on the highway.

That gives 35 X 1 +60 X 2, =155 miles. You only went 150.

But you're close!!

The correct answer is 1.2 hours (1hr.,12min.) in the city, 1.8hrs. on the

highway

1.2 X 35 + 1.8 X 60=42+108, =150

Here's the way to do it:

Time in City + Time on Hwy = 3hrs

From the formula Distance=Rate X Time,

Time=Distance / Rate.  We say T=D/R

Now we don't know the Distance traveled in the city, so let it be X

Therefore the Distance traveled on the hwy must be (240-X)

We're just about there.

For the city, T(c)=X/35

For the hwy.,T(h)=(240-X)/60

T(c) +T(h) = 3

X/35 + (240-X)/60 = 3

Multiply all terms by (35)(60)

60X+35(240-X)=(35)(60)(3)

60X+5250-35X=6300

25X=6300-5250

25X=1050

X=42

X was the distance traveled in the city.

Therefore TIME spent in the city=Distance/Rate

T(c)=42/35

=6/5

=1.2 hours

These Distance-Time-Rate problems are not easy. Again, I applaud

your effort.

For the second problem, Speed means Rate

From D=RT, R=R/T

R=35035/31.45

R=1114mph

Note that the 31hrs.27 minutes has to be changed into strictly hours.

I did this by saying 27 minutes is 27/60 of an hour. 27/60=0.45

Thus, 31+0.45, or 31.45 hours

And there you go!

Cheers

Answer 3

first problem:

Wrong; I got 1_1/5 hour (1 hr and 12 min.).

The way I did it was:

formula for distance -- d=rt (distance = rate*time)

Break up the 150 miles into two parts, one for the city and one for the highway (rate * time). Use "t" for the time in the city and "3-t" (the 3-hour total minus the city time) for the time in the highway.

Equation: 150 = 35t + 60(3-t)

---------------150 = 35t + 180 - 60t

-------------- -30 = -25t

-------------- 6/5 = t = 1_1/5 hour, or 1 hour and 12 min.

check:

highway time = 3 - 1_1/5 hour = 1_4/5 hour = 9/5 hour

total distance = city rate*time + highway rate*time

------------ = (35 * 6/5) + (60 * 9/5)

------------ = 42 + 108 miles

------------ = 150 miles

second problem:

speed = miles per hour

Rewrite 31 hours and 27 minutes as 31 and 27/60 hours, which reduces to 31 and 9/20 hours. Rewrite this as an improper fraction (629/20). Divide 35,035 (miles) by 629/20, multiplying 35,035 by the reciprocal (20/629).

Answer 4

A hint: I typically avoid questions who use all caps.  You may have asked calmly/nicely in previous attempts, but that doesn't matter to people like myself who just logged in.

For the first one, let x be the number of hours in the city and y be the number of hours on the highway.

Then 35x is the number of miles in the city and 60y is the number of miles on the highway.

---------

From the information, we can make two equations:

Number of miles in the trip.

35x + 60y = 150.

Number of hours total.

x + y = 3.

Solve for x (since it's the number of hours in the city) to get your answer.

Answer 5

wrong

you have to set it up as 2 equations

you know distance = velocity * time

here you have 2 velocities with 2 times so...

d=v1*t1 + v2*t2

which equates to :

150=35*t1 + 60*t2

now...

you know the total time spent was 3 hours so...

t1+t2=3

which can be broken down to mean:

t1=3-t2

so now set up the equation as

150=35(3-t2) + 60*t2

solving...

150=105-35*t2 + 60*t2

150= 105 + 25*t2

45=25*t2

t2= 45/25 = 1.8 hrs

if t2=1.8 hrs then t1 must be the remainder of the 3 hours so

t1= 1.2 hours   ....that is the city driving time

as for the other question

speed is miles per hour so:

# of hours = 31+ 27/60 = 31.45

average speed is: 35,035/31.45 = 1114 mph

:)