Answer:
36
Step-by-step explanation:
Here is the correct and complete question: The units digit of a two-digit number is twice the tens digit. If the digits are reversed, the new number is 9 less than twice the original number. What is the original number?
Lets assume the original number be"10y+x". (x is unit digit and y is 10th digit)
∴ if number is reversed then resulting number be "10x+y".
As given: x= 2y
and 
Now, solving the equation to get original number.

Distributing 2 to 10y and x, then opening the parenthesis.
⇒ 
subtracting by (2x+y) on both side.
⇒ 
subtituting the value of "x", which is equal to 2y.
∴ 
⇒ 
subtracting both side by (16y-9)
⇒ 
cross multiplying
We get, 
y=3
∵x= 2y

∴ x= 6
Therefore, the original number will be 36 as x is the unit number and y as tenth number.
66,80,35,24000
Those are the answers if I’m correct
Answer:
The volume of the triangular prism: 59.2
The value of the concrete used is: 16*4 = $64
Step-by-step explanation:
I think your question is missed of key information, allow me to add in and hope it will fit the original one. Please have a look at the attached photo
My answer:
As we know that, the formula to find out the volume of the triangular prism is:
V =
when h is the height and a&b are the length of the two square edges. So we have:
- V =
*4*4*7.4 = 59.2
To find the concrete used in the ramp if the cost of concrete is $ 4.00 per cubic foot, we need to know the area of the ramp, which is:
S = 4*4 = 16
Hence, the value of the concrete used is: 16*4 = $64
Answer:
1
or

Step-by-step explanation: