# Precalculus

I desperatly need help with these 3 problems anybody who can help?

1-Two trucks can carry loads of coal in a ratio of 5 to 2 the smaller truck has a capacity 3 tons less than that of the larger truck.What is the capacity of the larger truck?

2-Darnell drives about 15,000miles each year.he is planning to buy a new car.The car he wants to buy averages 20 miles on one gallon of gasoline.He has decided he would buy another car if he could save at least \$200 a year in gasoline expenses.Assume gasoline costs \$1.20 per gallon.What is the minimum number of miles per gallon that would fulfill Darnell’s criteria?

3-The speed of the currentin Puget Sound is 5 milesper hour.A barge travels with the current 26 miles and returns in 10 2/3 hours.What is its speed in still water

I only ask for the equation of the problem dont give me a straight answer since my theacher wants the process if you cant answer it do you know somewhere were they can please and thanks.

1-Two trucks can carry loads of coal in a ratio of 5 to 2 the smaller truck has a capacity 3 tons less than that of the larger truck.What is the capacity of the larger truck?

If I’ve understood your question correctly, the larger truck carries 5x and the smaller truck carriers 2x. The small truck would carry the large truck’s load if it had 3 tons more capacity (2x + 3 = 5x). Solve for x and 5x would be the larger truck’s capacity.

2-Darnell drives about 15,000miles each year.he is planning to buy a new car.The car he wants to buy averages 20 miles on one gallon of gasoline.He has decided he would buy another car if he could save at least \$200 a year in gasoline expenses.Assume gasoline costs \$1.20 per gallon.What is the minimum number of miles per gallon that would fulfill Darnell’s criteria?

To answer this question you need either a) the amount of gas he spends in his current car or b) the miles/gallon on his current car. I think you’re missing something here, or you’ve typoed.

3-The speed of the currentin Puget Sound is 5 milesper hour.A barge travels with the current 26 miles and returns in 10 2/3 hours.What is its speed in still water

The barge returning would travel x - 5 miles per hour, assuming that x is the barge’s speed and the -5 miles per hour is the current in Puget Sound (because on the return trip it goes against the current). Therefore (32/3)(x - 5) = 26. Solve for x.

just to make sure does the answer for problem #3 is 8 mbh?

Uh, no, it’s 7.4375 or 119/16. When you say it travels with the current 26 miles and comes back in 10 2/3 hours, do you mean <b>just the return trip</b> or <b>the whole trip, including the voyage with the current</b>?

Hummm I think it asks what is the avarage speed of tha barge in the all around trip

im no good in these verbal problems and in rational equations and partial fractions

I mean, what took 10 2/3 hours? Just the trip back, or the trip there and back combined?

My bad is the return trip,sorry

Then the answer is 7.4375. If you don’t get it, here’s how I got it:

(32/3)(x - 5) = 26

Multiply the left side
32x/3 - 160/3 = 26

Multiply all terms by 3
32x - 160 = 78

Move 160 to the right side
32x = 78 + 160

32x = 238

Divide through by 32
x = 238/32

238/32 = 7.4375

you were right sorry it does give me what you say i wonder why the book says 8 miles? but just to know what is he answer for question #1 and please forgive me for being such a bother

Question 1’s really easy. It’s just 5 tons I had my doubs thats why your really good at this man it is that i just suck at these verbal problems equations arent that much of a pronblem for me but verbal i hate those and once again i ask for forgiveness for being such a bother you really helped me:yipee:

No problem. (and try to breathe in your sentences once in a while :P)

I got and itsy bitsy problem here it is

The time t in seconds that it takes an object at rest to fall a distance of s meters is given by the equation t=square root of 2s/g in this formula,g is the accelaration due to gravity in meters per second squared.on the moon,a rock falls 7.2 meters in 3 seconds

1-write an equation that models the situation
2-what is the accelaration due to gravity on the moon?

t = sqrt(2s / g)

replace both variables with your numbers
3 = sqrt (14.4 / g)

square both sides of the equation
9 = 14.4 / g

multiply both sides by “g”
9g = 14.4

divide through by 9
g = 14.4 / 9

g = 1.6 Which is the acceleration due to gravity on the moon, that I have always been told to use, in my equations.

Cless, you really are good at those things, aren’t you?

Cless is our math god. He had a say in my piddly graphing thread as well.

Math is just my strongest subject, so I try to help out whenever I can It’s good to know that somebody around here has mastered the forbidden arts, 'cause I feel my skin crawl whenever I see equations ^^;;

Well i like math but is that i simply hate verbal problems,o and Cless remember the probem that you said had no answer it seems that the teachers guide had the answer it was like 900 or something i have no idea how they did it,so what is your opinion