A motorist left Embu for Mairdal, a distance of 240 km, at 8:00 am and traveled at an average speed of [tex]$90 \, \text{km/hr}$[/tex]. Another motorist left Nairobi for Embu at 8:30 am and traveled at [tex]$100 \, \text{km/hr}$[/tex]. Find:

- The time they met.



Answer :

To solve this problem, we need to determine the time at which the two motorists meet each other.

1. Define Variables and Known Information:
- The distance between Embu and Mairdal is 240 km.
- The first motorist leaves Embu at 8:00 AM and travels at an average speed of 90 km/hr.
- The second motorist leaves Nairobi at 8:30 AM and travels at an average speed of 100 km/hr.

2. Establish equations for distances traveled:
- Let [tex]\( t \)[/tex] be the time in hours after 8:00 AM when the two motorists meet.
- The distance covered by the first motorist when they meet is [tex]\( 90t \)[/tex] km, since distance = speed × time.
- The second motorist starts 0.5 hours later. Hence, the time traveled by the second motorist when they meet is [tex]\( t - 0.5 \)[/tex] hours.
- The distance covered by the second motorist when they meet is [tex]\( 100 \times (t - 0.5) \)[/tex] km.

3. Set up the equation considering the total distance:
- The sum of the distances covered by both motorists should equal the total distance between Embu and Mairdal.
- Therefore, we have the equation:
[tex]\[ 90t + 100(t - 0.5) = 240 \][/tex]

4. Simplify and solve for t:
- First, expand and simplify the equation:
[tex]\[ 90t + 100t - 50 = 240 \][/tex]
[tex]\[ 190t - 50 = 240 \][/tex]
- Add 50 to both sides:
[tex]\[ 190t = 290 \][/tex]
- Divide both sides by 190:
[tex]\[ t = \frac{290}{190} \approx 1.526 \][/tex]

5. Interpret the result:
- The time [tex]\( t \approx 1.526 \)[/tex] hours after 8:00 AM is when the two motorists meet.
- To convert this into a more understandable time, we break it down into hours and minutes.
- [tex]\( 0.526 \)[/tex] hours is approximately [tex]\( 0.526 \times 60 \approx 31.578 \)[/tex] minutes.

6. Determine the exact meeting time:
- Since 1.526 hours after 8:00 AM is approximately 1 hour and 31.578 minutes, the motorists meet at around 9:31 AM.

Therefore, the two motorists meet at approximately 9:31 AM.