shrey2287 wrote:At a certain store, each notepad costs x dollars and each marker costs y dollars. If $10 is enough to buy 5 notepads and 3
markers, is $10 enough to buy 4 notepads and 4 markers instead?
Since $10 is enough to buy 5 notepads at $x each and 3 markers at $y each, we get:
5x + 3y ≤ 10.
The question stem asks whether $10 is enough to buy 4 notepads and 4 markers:
4x + 4y ≤ 10
2x + 2y ≤ 5
x+y ≤ 2.5.
Question stem rephrased: Is x+y ≤ 2.5?
(1) Each notepad costs less than $1.
(2) $10 is enough to buy 11 notepads.
It is important to recognize not only how a problem is restricted but also how it ISN'T.
Neither statement restricts the cost of the MARKERS (y).
Try EXTREME values.
If x = .01 and y = .01, both statements are satisfied and 5x + 3y ≤ 10.
In this case, x + y = .01 + .01 = .02, which is less than 2.5.
If x = .01 and y = 3, both statements are satisfied and 5x + 3y ≤ 10.
In this case, x + y = .01 + 3 = 3.01, which is NOT less than 2.5.
Thus, the two statements combined are INSUFFICIENT.
The correct answer is
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