Two cars started from the same place at the same time but travelled in opposite directions. After 9 hours they were 910 kilometers apart. If the speed of one car is 10 kilometers per hour slower than the other what were their speedss per hour

Step-by-step explanation:

To make this easier we are going to make a table and fill it in with the pertinent information. That's the first step; the second one is figuring out how to use the information in the table to come to some sort of a viable and reasonable (and hopefully correct) answer. The table will look like this:

                     d        =        r        *        t

Car 1

Car 2

What we know first off is that the time in question, the IMPORTANT time is 9 hours. That they left at the same time doesn't give us any numbers to put into our table or any useful information. We are looking at what happens at 9 hours. So that's what goes into the t column:

                    d        =        r        *        t

Car 1                                                   9

Car 2                                                  9

What we are then told is that after this 9 hours they are a certain distance apart. We'll come back to that. One car is traveling 10 km/h slower than the other, but since we don't know what the rate of the other car is either, they are both unknown. And it just so happens that this the information we are asked to solve for.

                  d        =         r        *       t

Car 1                                r        *       9

Car 2                           r - 10     *       9

Now, since d = rt, we multiply the rate times the time and fill in the distance each has gone in 9 hours:

               d        =        r        *        t

Car 1       9r       =        r        *       9

Car 2   9r - 90  =     r - 10     *       9

The distance between these 2 cars after that 9 hours is 910 km, therefore:

distance that car 1 traveled + distance that car 2 traveled = 910 km:

9r + 9r - 90 = 910 and

18r - 90 = 910 and

18r = 1000 so

r = 55.56 km/hr

and the other car is going 10 km/hr slower at 45.56 km/hr

step-by-step explanation:

12: 00 p.m. to 7: 00 p.m. is a total of 7 hours.

4: 00 p.m. to 7: 00 p.m. is a total of 3 hours.

this means that from 4: 00 p.m to 7: 00 p.m. this represents 3/7 of what was lost from 12: 00 p.m. to 7: 00 p.m.

after knowing this, after doing 11,600 - 6,800 = 4,800

4,800 represents 3/7 of what was lost for 7 hours.

we then divide 4,800 by 3 which gets 1,600.

because we know that 1,600 represents 1/7 of how much water was lost, we just have to multiply by 7, which gets 11,200.   after adding 11,200 to how much water was left at 7: 00 p.m. which was 6,800. 11,200 + 6,800 = 18,000

this means that the pool originally had 18,000 gallons in the pool.

you can also check your work by doing 18,000 - 4(1600), which becomes           1800 - 6400 which gets you 11,600.