help with math please?

Question

1.93 is what percent of 300

2. if y varies directly as x and y= 8 when x= 3, find y when x= 5

3. if y varies inversely as x and y= 15 when x= 3 find y when x= 5

4. how heavy is an 800-foot reel of cable if a piece 6 feet long weigs 5 pounds

5. a price of 180 was increased to 207. find the percent of increase

6. a stero normally selling for 320 is discounted 18% find the sale price

7. find P(at least 5)

Answer 1

1. 93 is what percent of 300
93/300 = .31
% = 31

2. if y varies directly as x
y = kx
and y= 8 when x= 3,
8 = 3k
8/3 = k
find y when x= 5
y = 8(5)/3 = 40/3

3. if y varies inversely as x
y = k/x
and y= 15 when x= 3
15 = k/3
45 = k
find y when x= 5
y = 45/5
y = 9

4. how heavy is an 800-foot reel of cable if a piece 6 feet long weigs 5 pounds
the number of 6 ft pieces times the weight of a 6 ft piece
(800/6)(5) = 666 2/3 pounds

5. a price of 180 was increased to 207. find the percent of increase
We start with 180, so that is the whole
(207 - 180)/180 = 27/180 = .15 (15%)

6. a stero normally selling for 320 is discounted 18% find the sale price
If the discount is 18%, the price is (100 - 18)%
.82(320 = 262.40

7. find P(at least 5)
This old guy can only scratch his head at this one???

Answer 2

1) Assume 93 is x percent of 300.
x percent of 300 is 300(x/100) = 93
3x=93
x=31
So, 93 is 31 percent of 300.

2) if y varies directly as x, then y=kx
8=k(3)
k=8/3
y=(8/3)x
when x=5, y=(8/3)(5)=40/3=8

6)original price 320. discount 18%
18% of 320 = 320(18/100)=57.60(discount)
320-57.60=262.40(sale price)

7) Incomplete question.

Answer 3

If you have so many questions, put this in the Education section called "homework".

Alot of these are proportional type problems. For example #2.
y = kx (y varies directly with x)
Then y1/y2 = x1/x2 so 3/5 = 8/y2 3*y2=40 etc.

Answer 4

You should only ask math questions one at a time if you want good answers, i'll answer number one

1. 300x=93, 93/300=0.31=31%

I think...

Answer 5

4) 666.5pounds

Sorry, but this is the only one i figured, not sure if it is right

Answer 6

1.31%
2.y=10
3.y=13
4.666.67lbs
5.15%
6.$262.40
7.?

Answer 7

1.31
thats all ill do, listen to yo teacha and LEARN!!!!