when you reverse the digits of a certain two-digit number you decrease its value by 45. What is the number if the sum of its digits is 5

The number is 50.

Step-by-step explanation:

We need to understand the problem and convert it into a mathematical equation, or a series of equations. That way, we can solve them with ease.

The first thing we can do is to assign variables to represent the values that we do not know.

Let us assign the first number to be = x and the second number to be = y.

Important!

At this point, we must put their place values into consideration.

Since we are dealing with a two-digit number, we only have tens and units.

We will account for the place values of the variables assigned (x and y) by multiplying them by 10 and 1

x is the tens place value. To occupy this place value, it will become 10x

y is the unit place value. To occupy this place value, it will become 1 X y = y

This means that the original number is of the format x y

To convert this to an equation, it will become 10 (x) + y

Once the number order is reversed we will have 10 (x) + y = 10(y) + x - 45

grouping like terms

10x-x - 10y +y = - 45

9x -9y = - 45

From the second statement, we also have that x + y = 5

hence we have two equations x + y = 5   equation 1

                                                  9x -9y = - 45 equation 2

solving simultaneously, we have that the two numbers are 0 and 5

The number therefore, is 50

x = 5 and y = 0

56.6

step-by-step explanation:

the ratio of the perimeters is equal to the scale.

the ratio of the areas is equal to the square of the scale.

34 / 20 = k

a / 19.6 = k²

substituting:

a / 19.6 = (34 / 20)²

a = 19.6 (34 / 20)²

a ≈ 56.6