Bunuel
Of the people who donated money to a certain local theater last year, 1/4 donated $20 or less and 2/3 donated more than $20 but less than $1,000. If the average (arithmetic mean) amount donated by the people who donated more than $20 but less than $1,000 was $180, what was the average amount donated by the people who donated $1,000 or more?
(1) The average amount donated by the people who donated less than $1,000 was $132.
(2) The average amount donated by the people who donated more than $20 was $360.
Attachment:
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We have three categories of donors
1) Who donated $20 or less - We will refer to this category as
Group 12) Who donated more than $20 but less than $1,000 - We will refer to this category as
Group 22) Who donated more than $1,000 - We will refer to this category as
Group 3Assume that the total number of donors is \(12x\) (LCM of 3x and 4x).
Number of people in each group- Group 1: \(\frac{1}{4} * 12x = 3x\)
- Group 2: \(\frac{2}{3} * 12x = 8x\)
- Group 3: \(12x - 11x = x\)
...If the average (arithmetic mean) amount donated by the people who donated more than $20 but less than $1,000 was $180...Amount Donated- Group 1: \(p\)
- Group 2: \(180*3x\)
- Group 3: \(q\)
Question:\( \frac{q}{x}\) ?
Statement 1(1) The average amount donated by the people who donated less than $1,000 was $132.\(\frac{180*3x + p }{ 11x}= 132\)
We don't have any information given in the premise or in this stem to calculate \(q\). Hence, the statement alone is not sufficient. We can eliminate A and D.
Statement 2(2) The average amount donated by the people who donated more than $20 was $360.\(\frac{180*3x + q }{ 17x }= 360\)
\(180*3x + q = 360 * 17x\)
\(q = 360 * 17x - 180 * 3x\)
\(q = x(360 * 17 - 180 * 3)\)
\(\frac{q}{x} = (360 * 17 - 180 * 3)\)
We have a definite answer. Hence, this statement alone is sufficient.
Option B