Jessica is selling books during the summer to earn money for college. She
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Answer:
Speed of the first car = x = 35km/hr
Speed of the second car = 25km /hr
Step-by-step explanation:
The calculation of speeds of the cars is given below:-
Assume that the speed of the 1st car which is opening from A = x km/hr
and assume the Speed of the 2nd car which is starting from B
= y km/hr
As we know that
Time = Distance ÷ Speed
So, the distance lies between two places i.e. A and B are
80km d = 80 km
1. now when the car moves in the similar direction
So, the corresponding speed of them = (x + y)km/hr
Time = 8hr
d = 80km
2. when two cars moving in the inverse direction,
So, the corressponding speed = (x - y) km / hr
Time = 1 hr 20 minutes
That means
= (1 + 20 ÷ 60) hr
= (80 ÷ 60)
= 4/3 hr
d = 80km
Now
4 ÷ 3 = 80 ÷ (x -y)
x -y = (80 × 3) ÷ 4
x - y = 60 ..... (ii)
Now, we will sum equation 1 and equation 2 we will get
2x = 70
x = 35
now, Put x = 35 in (i) we will get
y = 25
Speed of the first car = x = 35km/hr
Speed of the second car = 25km /hr