Answer:
He drove 200 km at 100 km/h and 270 km at 90 km/h
Step-by-step explanation:
Distance = Speed × Time
<em>Assume that Kareem drove at 100 km/h for x hour</em>
∵ Kareem drove at 100 km/h for x hours
∴ He drove a distance = 100 × x
∴ He drove a distance = 100 x km
∵ He took 5 hours in whole trip
- Subtract x from 5 to find the time that he took in the rest
of the trip
∴ The time of the rest of the trip = 5 - x hours
∵ For the rest of the trip he drove at 90 km/h
∴ He drove a distance = 90 × (5 - x)
∴ He drove a distance = 450 - 90 x
∵ He drove 470 km in whole trip
- Add the two distance and equate the sum by 470
∴ 100 x + 450 - 90 x = 470
- Add the like terms in the left hand side
∴ 10 x + 450 = 470
- Subtract 450 from both sides
∴ 10 x = 20
- Divide both sides by 10
∴ x = 2
<em>Substitute the value of x in each distance to find the distance of each part</em>
∵ The distance of the first part = 100 x
∴ The distance of the first part = 100(2)
∴ The distance of the first part = 200 km
∵ The distance of the second part = 450 - 90 x
∴ The distance of the second part = 450 - 90(2) = 450 - 180
∴ The distance of the second part = 270 km
He drove 200 km at 100 km/h and 270 km at 90 km/h
