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Topic: How can I solve these problems?**Question:**
1) train travels 4 hrs at 60 miles per hour and 2 hrs at 75 miles per hour.
what is the train's average rate for 6 hours?
2) a saline solution is 20% salt. How many gallons of water must be added to dilute the mixture to 8 gals of 15% saline solution?
thank you for your help....

July 19, 2019 / By Felina

I can answer the first question, but the second one is not coming to me right away. How you solve the first one is you have to figure out how far the train goes first. So, take 4 hrs at 60 mph and you get a distances of 240 miles. Do the same for the second part, 2 hrs at 75 mph and you get 150 miles. Add these two together (240+150) and you get a total of 390 miles the train went. It traveled for 6 hours. To get the average divide the total traveled by the time traveled 390 miles/6 hours= 65 miles per hour. My apologies for not being able to help with the second problem.

👍 136 | 👎 4

Did you like the answer? It is true for everyone, you are not alone. The reason I think is that when we answer others problems we are not emotionally attach to the problem, we look at it objectively and suggest really feasible answers. If others chose your answers as best and take your advice, it is proof that you are actually an intelligent and good human being. It is just that in case of your own problems, you are having another input: emotions. I have tries it in past, detach emotionally first and then think of the solution. If you can do it, you have the solution. If you can't, you ask others.

It's easy because you are able to lay aside the jumbled emotions and think rationally, whereas the person experiencing the problem has to deal with the emotions. When they're your own problems... you're the one dealing with the emotions. Even by answering THIS question, I somewhat prove my point. I too have no problem figuring out what someone else should do, but I always have to ask my friend's advice for my own problems. And they always have great answers. And I know that the same thing happens to me for the same reason it happens to you. But it still doesn't mean I can change that about myself. Neither can you, unless you learn to turn off your emotions, and that's really not what you're after at all, is it?

1. its a total of 6 hours at (60x4 hours and 75x2 hours) (60x4) + (75x2) =390 miles in total over 6 hours. To find the average you must divide the total by the number of hours. so, 390 divide by 6.. gives you an average of 65 miles per hour. Don't know about number two....sorry!

👍 50 | 👎 2

The first one is as others have answered it. The second is done like this (15/100)*8 = (20/100)*x x = .9 gallons of 20 % solution.

👍 47 | 👎 0

for the first series, 4+8+12+16+20+24+28+32 we have a1 = 4, a8 = 32, n = 8. Sn = n(a1 + an)/2 = 8(4+32)/2 = 4(36) = 144. for the second series, 7+2+(-3)+(-8)+(-13)+(-18) we have a1 = 7, a6 = -18, n = 6 Sn = n(a1 + an)/2 = 6(7+(-18))/2 = 3(7-18) = 3(-11) = -33

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