A bicycle store costs ​$3900 per month to operate. The store pays an average of ​$55 per bike. The average selling price of each bicycle is ​$185. How many bicycles must the store sell each month to break​ even?

The store must sell
  
bicycles each month to break even.
​(Type a whole​ number.)

ANSWER CORRECTLY

To determine the number of bicycles the store must sell each month to break even, we need to subtract the cost of each bicycle from the selling price and find out how many bicycles will cover the monthly operating cost.

Let's calculate the profit per bicycle:
Profit per bicycle = Selling Price - Cost per bicycle
Profit per bicycle = $185 - $55 = $130

Now, we need to find out how many bicycles will cover the monthly operating cost:
Number of bicycles to break even = Operating cost / Profit per bicycle
Number of bicycles to break even = $3900 / $130 = 30

Therefore, the store must sell 30 bicycles each month to break even.

If a plane can travel 470 miles per hour with the wind and 410 miles per hour against the​ wind, find the speed of the wind and the speed of the plane in still air.

What is the speed of the​ wind?
  
mph

Let's assume the speed of the plane in still air is "P" mph and the speed of the wind is "W" mph.

When the plane is flying with the wind, its speed is increased, so we can say:
P + W = 470 mph ..................(1)

When the plane is flying against the wind, its speed is decreased, so we can say:
P - W = 410 mph ..................(2)

Now we can solve these two equations to find the values of P and W.

Adding equations (1) and (2), we get:
(P + W) + (P - W) = 470 + 410
2P = 880
P = 440 mph

Substituting this value of P into equation (1), we get:
440 + W = 470
W = 470 - 440
W = 30 mph

Therefore, the speed of the wind is 30 mph.

What is the speed of the plane in still​ air?

  
mph

The speed of the plane in still air is 440 mph.

A metalworker has a metal alloy that is 20​% copper and another alloy that is 55​% copper. How many kilograms of each alloy should the metalworker combine to create 90 kg of a ​48% copper​ alloy?

The metalworker should use
  

kilograms of the metal alloy that is 20​% copper and kilograms of the metal alloy that is ​55% copper.
​(Type whole​ numbers.)

Let's assume the metalworker uses "x" kilograms of the alloy that is 20% copper, and "y" kilograms of the alloy that is 55% copper.

To find the amount of copper in the resulting 90 kg alloy, we can set up the following equation:

(20% of x) + (55% of y) = 48% of 90

Simplifying the equation, we get:

(0.2x) + (0.55y) = 0.48(90)

0.2x + 0.55y = 43.2

We also know that the total weight of the alloy is 90 kg, so we have the equation:

x + y = 90

We have two equations:

0.2x + 0.55y = 43.2 .....(1)
x + y = 90 ...............(2)

We can solve these equations simultaneously to find the values of x and y.

Using the method of substitution or elimination, we find that when we multiply equation (2) by 0.2 and subtract it from equation (1), we can solve for y:

0.2x + 0.55y - (0.2x + 0.2y) = 43.2 - 0.2(90)
0.35y - 0.2y = 43.2 - 18
0.15y = 25.2
y = 25.2 / 0.15
y = 168

Substituting the value of y into equation (2), we can solve for x:

x + 168 = 90
x = 90 - 168
x = -78

Since we cannot have negative values for the kilograms of the alloy, we know that the metalworker must use 168 kg of the alloy that is 55% copper and 90 - 168 = -78 kg of the alloy that is 20% copper.

Therefore, the metalworker should use 168 kg of the metal alloy that is 55% copper and 0 kg of the metal alloy that is 20% copper.

Determine whether the ordered pair is a solution of the given system.

​(2​,13​);
y > 2x + 3
y < 3x + 8

Is ​(​2,13​) a solution of the given​ system?

To determine if the ordered pair (2, 13) is a solution of the system, we need to substitute the values of x and y into each inequality and check if both inequalities are satisfied.

For the first inequality, y > 2x + 3, we substitute x = 2 and y = 13:

13 > 2(2) + 3
13 > 4 + 3
13 > 7

This inequality is true, as 13 is indeed greater than 7.

For the second inequality, y < 3x + 8, we substitute x = 2 and y = 13:

13 < 3(2) + 8
13 < 6 + 8
13 < 14

This inequality is also true, as 13 is indeed less than 14.

Since both inequalities are true when we substitute x = 2 and y = 13, the ordered pair (2, 13) is indeed a solution of the given system.

Cherries cost ​$​4/lb. Grapes cost ​$1.50​/lb. You can spend no more than ​$9 on​ fruit, and you need at least 3 lb in all. Create a graph showing the amount of each fruit you can buy.

Use the graphing tool to graph the system.