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24 Sep 2025, 00:49
Kudos
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C
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
25%
(medium)
Question Stats:
75% (00:59) correct
25%
(01:18)
wrong
based on 80
sessions
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Not Attempted Yet
If from 1991 to 2000, the number of students of School X tripled, how many number of students of the school were there in 1991?
(1) From 2000 to 2009, the number of students of the school doubled.
(2) From 2000 to 2009, the number of students of the school increased by 120.
(1) From 2000 to 2009, the number of students of the school doubled.
(2) From 2000 to 2009, the number of students of the school increased by 120.
24 Sep 2025, 09:12
Kudos
Bookmarks
Let, number of students in 1991 = x
Number of students in 2000= 3x
We need to find x
(1) From 2000 to 2009, the number of students of the school doubled.
Number of students in 2009= 2*3x=6x
Insufficient
(2) From 2000 to 2009, the number of students of the school increased by 120.
Number of students in 2009= 3x+120
Insufficient
(1)&(2) 6x=3x+120 ; 3x=120 ; x=120/3=40
Sufficient
C
Number of students in 2000= 3x
We need to find x
(1) From 2000 to 2009, the number of students of the school doubled.
Number of students in 2009= 2*3x=6x
Insufficient
(2) From 2000 to 2009, the number of students of the school increased by 120.
Number of students in 2009= 3x+120
Insufficient
(1)&(2) 6x=3x+120 ; 3x=120 ; x=120/3=40
Sufficient
C
24 Sep 2025, 18:26
Kudos
Bookmarks
1991 to 2000 tripled. No. of students in 1991 =?
Option 1:
2000-2009 students doubled. nothing to say from here . not sufficient
Option 2:
2000 to 2009 no. of students increased by 120. (still nothing sufficient alone from here )
Option 1+2:
if increasing by 120 amounts to double the number then the initial number is also 120. Hence in 2000 there is 120 students.
Now we know the number of students tripled from 1991 to 2000. So if in 2000 the number is 120 then in 1991 the number is 120/3=40 Hence both option together sufficient (C)
Option 1:
2000-2009 students doubled. nothing to say from here . not sufficient
Option 2:
2000 to 2009 no. of students increased by 120. (still nothing sufficient alone from here )
Option 1+2:
if increasing by 120 amounts to double the number then the initial number is also 120. Hence in 2000 there is 120 students.
Now we know the number of students tripled from 1991 to 2000. So if in 2000 the number is 120 then in 1991 the number is 120/3=40 Hence both option together sufficient (C)
Bunuel
