Was out 2 days of school, need some help on a lesson?

Question

I was out 2 days sick last week of school and the unit test is on tuesday. I was wondering if someone could help me figure out these problems so I can prepare. Thx in advance.

1. When an electric current is 32 A (amperes), the electromotive force is 288 V (volts). Find the force when the current is 65 A if the force varies directly as the current.

2. A restaurant buys 20 lbs of ground beef to prepare 110 servings of chili. At this rate, how many servings can be made with 30 lbs of ground beef?

3. The amount of chlorine needed for a pool varies directly as the size of the pool varies. If 5 units of chlorine is the amount needed for 2500 L of water, how much chlorine is needed for 3750 L of water?

4. The odometer on the Goldmans’ car is not measuring distance correctly. For a 220-mi trip the odometer registers only 216.7 mi. On their return trip, the Goldmans detour due to road repairs. If the odometer registers 453.1 mi for the round trip, how many actual miles was the detour?

Answer 1

1. not so good with electrical sorry

2. 165 formula: half of 20 is 10 half of 110 is 55 so add 55 + 110=165

3. 7.5 formula: 3750-2500=1250 which is half of 2500 divide 5 in half you get 2.5 add that to the original 5 =7.5

4. 453.1/2=226.55-216.7=9.85

Answer 2

1. For a direct variation problem you can either set up a proportion, which i think is easier, or you can use the equation: y= k x

the proportion for this should be:

35/ 288 = 65 / v
then you cross multiply to get the equation:

35v = 288 ( 65)
35v = 18720
v = 534.85714285714285714
you can round it to: 535 V
if you have to put it into scientific notation based on the number of significant digits it would be:

5.3 x 10^2 ( that means ten squared)


2. this can also be solved using a proportion

20 / 110 = 30 / x
20x = 30 (110)
20 x = 3300
x = 165 servings of chili

i hope you understand how to do this. you set up a proportion. i tried to make it so they were overtop of each other like this:

20 = 30
---- ----
110 x

but it kind of looks weird. if it helps you better to think of the proportions like that though, then that's all right.

3. another direct variation. that means another proportion:

5 = x
-------- ---
2500 3750

2500x = 5 (3750)
7.5 = x

it takes 7.5 units of chlorine

4. i think this is another direct proportion

220 = x
------ -----
216.7 453.1

216.7x = 220 (453.1)
x = 460

they drove 460 miles


i hope that this helped. if you have any more questions, feel free to ask me. i hope you understand how to do the direct proportions.

Answer 3

1. Set up ratios: 32/288=65/F where F =electromotive force
32F=288 x 65 Then cross multiply
F= (288 x 65)/32= 585 volts

2. Set up ratios: 20lbs ground beef/110 servings of chili = 30lbs of ground beef /c servings of chili
20/110=30/c
20c = 110 x 30
c = 165 servings of chili

3. 5 units of chlorine/2500L of water = C units of chlorine/3750 L of water
5 x 3750 = 2500C
C = 7.5 units of chlorine

4. 220 actual miles/216.7 miles on odometer = A actual miles/453.1 miles on odometer

220 x 453.1 = 216.7 x A
A = 460 actual miles

All these problems involve setting up ratios, then cross multiplying and solving for the variable.

Answer 4

isnt that against k12 copyright ???rules yea sick 2 days good one! how sick will you be when your parents find out your expelled [ i mean dude the wholeeee 30 point assignment]

Answer 5

two days out of school doesnt mean u wont get this much.. ur an A$$h&&&

Answer 6

You just want the answers! You don't want to learn