Three pupils John, Daniel and David contributed a total of $400 for a party. John contributed $30 more than Daniel while, David contributed three times as much as John. If David contributed $x, which one of the equations below can be used to find David's contribution?
Daniel -- x
John --- x+30
David --- 3(x+30)
solve for x, the plug into my definitions
x + x+30 + 3(x+30) = 400
Let's break down the information given in the question:
1. John contributed $30 more than Daniel: Let's say Daniel's contribution is "y". Therefore, John's contribution is "y + $30".
2. David contributed three times as much as John: Let's say David's contribution is "x". Therefore, John's contribution is "1/3 * x".
Now, let's use these equations to find David's contribution.
According to the question, the three pupils contributed a total of $400. So, the equation becomes:
(y + $30) + y + x = $400
Simplifying this equation, we get:
2y + $30 + x = $400
Now, let's substitute the value of John's contribution (1/3 * x) into the equation:
2y + $30 + (1/3 * x) = $400
Since the question asks for the equation that can be used to find David's contribution, we can rewrite the equation as:
2y + (1/3 * x) = $400 - $30
Combining like terms, we can simplify the equation to:
2y + (1/3 * x) = $370
Therefore, the equation that can be used to find David's contribution is:
2y + (1/3 * x) = $370