Help me with my 5 algebra 2 problem for 10 point's...... ?

Question

1 if y caries directly as x and y = 4 when = -2, find y when x = 30

a -4/15

b 60

c -60

d 4/15

2 the area A of a triangle varies jointly as the lengths of its bace b and height h. if A is 75 when b = 15 and h = 10, find A when b = 8 and h=6

a 12

b 48

c 24

d 96

3 if y varies inversely as x and y=2 when x=6, find y when x=36

a 1/6

b 6

c 3

d 1/3

4 the distance a car can travel on a certain amount of fuel varies inversely with ti's speed. If a car traveling 50 mph can travel 300 miles on 10 gallons of fuel, how far could the car travel on 10 gallons of fuel at 60 mph?

a 250miles

b 360miles

c 275miles

d 300miles

5 tomas can do a job in 4 hours. julia can do the same job in 6 hourse how many hours will it take the two of them to do the job if they work together

a 3.5

b 2.4

c 5

d 2

Answer 1

1) This is a proportion that is set up like this: y/x = 4/-2 = y2/30. To solve for y2, it's (4*30)/-2 = -60. To double check, 4/-2 = -2 and -60/ 30 also equals -2.

2) formula for area of a triangle is b * h * 0.5, so 8 * 6 * 0.5 = 24.

3)Again, proportions.. I'm guessing you must be having problems with solving them. Well, for this one you have to multiply 2 * 36 and divide that answer by 6 to get y = 12.

4)50/300 is equal to 60/x. (60*300)/50 = 360 miles

5) Find the average or mean: 4hours+6hours = 10hours total /2 people = 5 hours.

Answer 2

Let me make you think.  (I always make things harder then they have to be.)

1. This is saying y is directly related to x.  So, what formula would you use to get y=4, when x=-2?  HINT: It's mulitplication.  Now, plug in x=30 to determine y.

2. Same idea, but use A, b, and h.  What formula will get you 75 when plugging in 15 and 10?  HINT: It's multiple step.  Again, plug in 8 for b, and 6 for h, and circle the correct answer.

3. "Inversely" means y goes down in proportion to x going up.  What operation do you think can do that?  Come up with a formula for y=2 when x=6.  Then, substitute 36 for x to get the answer.

4.  Inverse again.  It's saying here that the faster the car goes, the less distance it can travel on the same fuel.  So you know that the relationship of speed to miles will be the same.  So you have 300 miles at 50 is the same as x miles at 60.  Solve for x.

5.  I say this is a trick question.  Double the effort doesn't always half the time.  But, let's assume for this problem that it does.  If they each work their full time, (6 and 4 hours) how long would it take to get half the job done (since each half would be done at the same time?)  Works like an average.

You didn't think I'd actually give you the answers did you?  You said you wanted help, not that you wanted to cheat!

William