help with rate-time-distance math???? HELP?

Question

a car started out from mephis toward little rock at the rate of 60 km/h. a sceond car left from teh same point two hours later and drove along the same route at 75 km/h. how long did it take for the second car to overtake the first?

please EXPLAIN your answer<3
and fyi, im doing my own homework, i got 80 minutes for this problem, but im almost sure its rong and i dont know why...

Answer 1

When the second car leaves, the first car is 120km down the road.

Since distance = time * speed, when the two cars meet you have this equation:

75t = 60t + 120

Solve for t.

Answer 2

d=rt
Car number 1: Car number 2:
60t 75(t-2) use distributive
Hours:Distance Hours:Distance
1 60 1 0
2 120 2 0
3 180 3 75
4 240 4 150
5 300 5 225
6 360 6 300
7 420 7 375

Im not going to go farther, but thats how you have to do it. Find the function rule then multiply

Answer 3

let the time taken by the second car to overtake = t hrs

time taken by first car to reach the crossing point = t + 2 hrs
(since first car started 2 hrs earlier)

distance travelled by first car = 60(t +2) km (speed *time)

distance travelled by second car = 75 t km

both the distances must be equal when meet

75t = 60(t+2)

75 t = 60t + 120

15t = 120

t = 120/15 = 8 hrs

Answer 4

im not sure if you are in calculus or if you do parametric equations so i'll try to explain in lamens terms

y=60x + 120 will represent first equation, (plus 120 because it is already ahead 2 hours and 2 hours at 60km/hr = 120 km)

y=75x will represent second,

. Now set the equations equal to eachother and solve for x. this is the time when the distance is equal. thus the time greater than what u solve for X is when it overtakes

75x=60x+120
15x=120
x=120/15
= 8 hours

the key for word problems is figuring out how to set them up

Answer 5

Mohammad sounds right to me Suni.

However, what you do is not over panic okay.
1.Take a deep breath.
2.Take qucik notes from boring teacher.
3.Just go their & come back.
4.math is the path to sucess.
5.Key numbers only Sunni.

Answer 6

2v_1+tv_1=tv_2

120+t60=75t

15t=120

t=120/15 h = 8h