Amy left City A at 6 am. She drove for 4 hours at 80 km/hr to reach City B.

Ally also left City A at 6 am, however she drove at 1.2 times the speed of Amy.

What time did Ally arrive in City B?

1 answer

First, let's calculate the distance between City A and City B based on Amy's travel.

Amy drove for 4 hours at a speed of 80 km/hr. The distance (D) she covered can be calculated using the formula:

\[ D = \text{speed} \times \text{time} \]

Substituting in the values:

\[ D = 80 , \text{km/hr} \times 4 , \text{hours} = 320 , \text{km} \]

Now, we know the distance from City A to City B is 320 km.

Next, we determine Ally's speed. Ally drove at 1.2 times Amy's speed:

\[ \text{Ally's speed} = 1.2 \times 80 , \text{km/hr} = 96 , \text{km/hr} \]

Now we can calculate the time it takes for Ally to travel the same distance of 320 km using the formula:

\[ \text{time} = \frac{\text{distance}}{\text{speed}} \]

Substituting in the values for Ally:

\[ \text{time} = \frac{320 , \text{km}}{96 , \text{km/hr}} \approx 3.33 , \text{hours} \]

This time can also be expressed in hours and minutes. Since \(0.33\) hours is approximately \(20\) minutes (since \(0.33 \times 60 \approx 20\)), we find that:

\[ \text{time} \approx 3 , \text{hours} , 20 , \text{minutes} \]

Now, Ally left City A at 6 am. Adding the travel time to her departure time:

\[ 6:00 , \text{am} + 3 , \text{hours} , 20 , \text{minutes} = 9:20 , \text{am} \]

Thus, the time Ally arrived in City B is:

\[ \boxed{9:20 , \text{am}} \]