Question

On a trip a car travels 80 miles in an hour and a half ,then was stopped in traffic for 30 mi , and then travels 100 miles during the next two hours . what was the cars average speed for the 4 hours trip.​

Answer 1

Answer:

45 mile/hr

Step-by-step explanation:

Time for first 80 miles = 1hr + ½hr = 90 min

Wasted time = 30 min

Time fof 100 miles = 2hr = 120 min.

Thus,

Total distance = 80 + 100 mile = 180 miles

Total time = 90 + 30 + 120 min = 4 hr

Average speed = 180/4 = 45 mile/hr

Answer 2

Answer:-

$\red{\bigstar}$ Average speed $\large\leadsto\boxed{\rm\purple{45 \: miles/hour}}$

• Given:-

$\pink{\dag}$ Distance travelled by car = 80 miles

$\pink{\dag}$ Time taken to cover 80 miles = 1½ hour → 60 + 30 min. = 90 min.

$\pink{\dag}$ Time in traffic = 30 min.

$\pink{\dag}$ Distance travelled after traffic = 100 miles

$\pink{\dag}$ Time taken to cover 100 miles = 2 hours → 120 min.

• To Find:-

Average speed of car for next 4 hours = ?

• Solution:-

We know,

$\boxed{\bf\green{Average \: speed [s] = \dfrac{Total \: Distance [d]}{Total \: time[t]}}}$

here,

✧ Total Distance = 80 miles + 100 miles

→ 180 miles

✧ Total Time = 90 min. + 30 min. + 120 min.

→ 240 min. $\: \: \: \: \: \: \dashrightarrow\bf{[1hr. = 60 min.]}$

→ 4 hours.

• Substituting in the Formula:-

✧$\large\boxed{\bf{s= \dfrac{d}{t}}}$

$\dashrightarrow\sf{s = \dfrac{180}{4}}$

$\dashrightarrow\large\bf\blue{s = 45 \: miles/hr.}$

Therefore, the average speed is 45 miles/hr.

$\pink{\bigstar}$ Know More:-

• Average speed is the total distance travelled by the object to the total time elapsed or time taken to cover that distance.

• In order to calculate the average speed of an object, we must know the Distance travelled by that object and the total time taken by the object to travel that distance.

$\red{\dag}$ $\sf{Average \: speed [s] = \dfrac{Total \: Distance [d]}{Total \: time[t]}}$

$\red{\dag}$ $\sf{Total \: time[t] = \dfrac{Total \: Distance [d]}{Total \: Speed [s]}}$

$\red{\dag}$ $\sf{Total \: Distance [d] = Total \: Speed [s] \times Total \: time [t]}$