A 2-bedroom apartment that rents for $520 a month is $40 less than twice the cost of a 1-bedroom apartment. What is the monthly rent of a 1-bedroom apartment?​

monthly rent of a 1-bedroom apartment= $280

Step-by-step explanation:

Let the  cost of 1 bed room apartment = x

And the cost of two bedroom apartment= 2x-40

Since the cost of of two bedroom apartment = $520  

Then the cost of one bed room part will be expressed as

520= 2x- 40

520+40 = 2x

560= 2x

x= 560/ 2

x= 280

Therefore the  cost of 1 bed room apartment = x= $280

c.

step-by-step explanation:

she should of added 9^2 and 12^2. that is because it is a^2+b^2=c^2. c^2 is the hypotenuse and should always be bigger than the other two numbers. which is why she should of added 9 squared and 12 squared together instead of 15 squared.