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21 Nov 2018, 08:12
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D
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
15%
(low)
Question Stats:
81% (01:18) correct
19%
(01:23)
wrong
based on 1151
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Claire paid a total of $1 .60 for stamps, some of which cost $0.20 each, and the rest of which cost $0.15 each. How many 20-cent stamps did Claire buy?
(1) Claire bought exactly 9 stamps.
(2) The number of 20-cent stamps Claire bought was 1 more than the number of 15-cent stamps she bought.
(1) Claire bought exactly 9 stamps.
(2) The number of 20-cent stamps Claire bought was 1 more than the number of 15-cent stamps she bought.
Pure algebraic questions like this one are no longer part of the GMAT Data Sufficiency syllabus.
For relevant Data Sufficiency questions, please check the Data Sufficiency forum:
Data Sufficiency Forum
Data Sufficiency Forum
21 Nov 2018, 10:36
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Answer D.
A) As there aren't that many options, we can just check them:
There have to be an even number of 0.15 stamps - otherwise we won't get a round number. So:
8*0.15+1*0.2=1.4 - not enough
6*.15+3*0.2=1.5 0 not enough
4*0.15+5*.2=1.6 - yes!
2*0.15 + 7*.2=1.7 - too much
0*0,15+9*.2=1.8 - too much
Sufficient!
B) As we've already seen from (1), this world for 4 0.15 stamps and 5 0.2 stamps. can it work for any others? No - if go less (3 and 4, say) we'll get less than 1.6, if we go more we'll get more. Sufficient!
A) As there aren't that many options, we can just check them:
There have to be an even number of 0.15 stamps - otherwise we won't get a round number. So:
8*0.15+1*0.2=1.4 - not enough
6*.15+3*0.2=1.5 0 not enough
4*0.15+5*.2=1.6 - yes!
2*0.15 + 7*.2=1.7 - too much
0*0,15+9*.2=1.8 - too much
Sufficient!
B) As we've already seen from (1), this world for 4 0.15 stamps and 5 0.2 stamps. can it work for any others? No - if go less (3 and 4, say) we'll get less than 1.6, if we go more we'll get more. Sufficient!
02 Jan 2019, 05:41
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adkikani
Let x be number of 20-cent stamps and y be number of 15-cent stamps.
So the question gives us
0.2 x + 0.15 y = 1.60
statement 1: x + y = 9 --> x = 9 - y --> plug in in first equation and solve for x and y --> sufficient
statement 2: x -1 = y --> x = y +1 --> plug in in first equation and solve for x and y --> sufficient
If needed, I got x = 4 and y = 5
