Marta bought several pencils. If each pencil was either a $0.23 pencil or a $0.21 pencil, how many $0.23 pencils did Marta buy?
1) Marta bought a total of 6 pencils
2) The total value of the pencils Marta bought was $1.30
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You can also look at this as follows: if she bought 7 pencils, she would spend at least 7*0.21 = $1.49. If she bought 5 pencils, she would spend at most 5*0.23 = $1.15. So if she spent $1.30, as we learn from Statement 2 alone, she must have bought exactly 6 pencils. So Statement 2 is sufficient alone (once we know that she bought 6 pencils, there can only be one combination of $0.23 and $0.21 pencils that give a total cost of $1.30, since the more $0.23 pencils she buys, the greater the cost will be).
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