Answer:
or

Step-by-step explanation:
we know that
The scale of the drawing is equal to divide the length of a building in the scale drawing by the actual length of a building
so
That means
15 cm in the drawing represent 37.5 ft in the actual
Remember that

Convert 15 cm to ft
divide by 30.48

substitute

or

That means
1.31 units in the drawing represent 100 units in the actual
Answer:
She made a mistake in Step 7.
Step-by-step explanation:
Step 1 through 6 are correct. Only from Step 6 to Step 7 the problem comes in: both sides of the equation are multiplied by x, however the x on the left side, by error, becomes 1. The correct state in Step 7 should look like this:

Answer:
960
Step-by-step explanation:
We start with the variable "x". Let's call "x" Raina's penny bank.
After adding 360 pennies, at the end, she has 5/8x, or 5/8.
So we start with
(1/4)x + 360 = 5/8x
Let's subtract 1/4x from both sides
360 = 5/8x - 1/4x
Remember, we need to use common denominators to subtract, so 1/4 becomes 2/8
360 = 5/8x - 2/8x
Now we simplify to get
360=3/8x
Multiply the reciprocal of 3/8 to both sides which is 8/3
360 * 8/3 = x
Answer is 960 pennies.
Therefore Raina's bank hold 960 pennies.
That is not a question so I can't help you but combined she did 7/4 or 1 3/4 hours