Everyone pls help to solve my Maths HW...!! It is too difficult!?

Question

1. After a 10% discount, the sales price of a bag is $100. Find the sales price before discount correct to the nearest cent.




2a) On a given map, the scal is 1:50 000. Find the length on the map representing a distance of 7.5 km.



2b) On a given map, the scale is 1:10 000. Find the area represented by2.5 cm^2 on the map. Leave your final answer in m^2.



3.Evalute the following arithmetic expressions with the help of your calculator. Express your final answers correct to 4 decimal places.

(a) 7^0

(b) 0/0

Answer 1

1. You need to find x.
.90 * x = 100
because you want .10 taken off.
x = 100 / .90 = 111.11

2. a. Set up a ratio with the kilometers changed to meters.
1 / 50000 = x / 7500
x = 7500 / 50000 = .15
then change x to centimeters.
x = 15 cm
b. do the same thing as above but change cm^2 to m^2. Since they are squared, you must move the decimal over 4 spaces instead of just 2.
1 / 10000 = 25000 / x
x = 25000 / 10000 = 2.5 m^2
3. a. anything to the 0 power is 1.
b. anything divided by 0 will produce an error in your calculator because it is undefined.

Answer 2

1. You can regard the scale ratio 1:50 as a fraction 1/50. The length of the model is: (1/50)*12m = 12*100cm / 50 12* 2cm = 24cm. 2. The length of the rectangle is x - 4 cm. The width of the rectangle is 2x + 1 cm. (a) Let P cm. be the perimeter of the rectangle. Then P is twice the sum of the length and the width. P = 2(x - 4 + 2x + 1) P = 2(3x - 3) P = 6x - 6 ........................(1) P = 6(x - 1). (b) In equation (1) from part (a) put P = 30: 6x - 6 = 30 Subtract 30 from each side: 6x - 36 = 0. (c) 6x - 36 = 0 Add 36 to each side: 6x = 36 Divide by 6: x = 6. The area of the rectangle is: 2(x - 4)(2x + 1) = 2 x 2 x 13 = 52 cm^2.

Answer 3

1. 111,11 c

2a. 3,75 cm

2b. 62500 sq.m

3a. 1,0000

3b. error

To Birdie: Yes I agree with 2a. I made a mistake doing multiplication instead of division. There is an easier consideration by working with maps. The scale 1:50 000 means that one cm. on the map contains 50 000 cm. on the ground. Or just 0,5 km correspondingly. So 7,5 km makes 15 cm on the map. (7,5 / 0,5 = 15)

Unfortunately you did a mistake by 2b. The scale 1:10 000 means 100 m in 1 cm on the map. Or 0,1 km in 1 cm on the map. 2,5 cm on the map make 250 m on the ground. The required area in this case results as 250 m x 250 m. or 62500 sq.m.

Answer 4

1. 110$