There was 2.5 inches of rainfall today. The total precipitation for the month is now 7.2 inches.

Which equation could be used to determine the amount of precipitation before today?

A. [tex]\( x - 2.5 = 7.2 \)[/tex]

B. [tex]\( x + 2.5 = 7.2 \)[/tex]

C. [tex]\( 2.5 - x = 7.2 \)[/tex]

D. [tex]\( 2.5 + 7.2 = x \)[/tex]

E. [tex]\( 7.2 + x = 2.5 \)[/tex]



Answer :

To solve this problem, we need to determine which equation correctly represents the relationship between the rainfall today, the total precipitation, and the amount of precipitation before today.

Given:
- Rainfall today = 2.5 inches
- Total precipitation for the month = 7.2 inches

Let's denote the amount of precipitation before today as [tex]\( x \)[/tex].

We know that the total precipitation for the month is the sum of the rainfall today and the precipitation before today. Therefore, the relationship can be expressed using the equation:

[tex]\[ x + \text{rainfall today} = \text{total precipitation} \][/tex]

Substituting the given values:
[tex]\[ x + 2.5 = 7.2 \][/tex]

Hence, the correct equation that can be used to determine the amount of precipitation before today is:
[tex]\[ x + 2.5 = 7.2 \][/tex]

To check this, we can solve the equation for [tex]\( x \)[/tex]:

[tex]\[ x + 2.5 = 7.2 \][/tex]

Subtracting 2.5 from both sides:
[tex]\[ x = 7.2 - 2.5 \][/tex]

[tex]\[ x = 4.7 \][/tex]

Therefore, the precipitation before today is 4.7 inches, verifying that the correct equation is:
[tex]\[ x + 2.5 = 7.2 \][/tex]