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10 May 2019, 02:09
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A
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
95%
(hard)
Question Stats:
40% (02:49) correct
60%
(02:44)
wrong
based on 141
sessions
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x boys can complete a work in 15 days and y girls can complete the same work in 24 days. Find the number of days taken to complete the work by (x – 8) boys and (y – 7) girls together.
Statement I: If the efficiency of boys is twice than that of girls and (x + y) = 27.
Statement II: If x = y, then the number of days taken by all the boys is half the number of days taken by all the girls
Statement I: If the efficiency of boys is twice than that of girls and (x + y) = 27.
Statement II: If x = y, then the number of days taken by all the boys is half the number of days taken by all the girls
16 May 2019, 21:16
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Note down the formula: W=RT (Work = Rate * Time)
R of 1 boy - (1/m)
R of 1 girl - (1/n)
W of x boys = x*(1/m)*15 = 1
W of y girls = y*(1/n)*24 = 1
statement 1 --
GIVEN : boys take 1/2 the time as compared to girls and x+y = 27;
m= 2n; thus, these variables will be cancelled out.
using the 2 equations, values of x and y can be retrieved.
SUFFICIENT
statement 2 --
when x = y, boys take half the time as compared to girls;
there are 2 unknown variables and only one equation
INSUFFICIENT
ANSWER: A
R of 1 boy - (1/m)
R of 1 girl - (1/n)
W of x boys = x*(1/m)*15 = 1
W of y girls = y*(1/n)*24 = 1
statement 1 --
GIVEN : boys take 1/2 the time as compared to girls and x+y = 27;
m= 2n; thus, these variables will be cancelled out.
using the 2 equations, values of x and y can be retrieved.
SUFFICIENT
statement 2 --
when x = y, boys take half the time as compared to girls;
there are 2 unknown variables and only one equation
INSUFFICIENT
ANSWER: A
General Discussion
10 May 2019, 04:22
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1 boy can do the work in day is 1/15 ...=> for x boys its x/15
1 girl can do the work in day is 1/24 ...=> for x boys its y/24
From Statement I: the efficiency of boys is twice than that of girls so x/15=2*y/24 also given x+y=27...from both eqns we get values of x,y so that we can get the number of days taken to complete the work by (x – 8) boys and (y – 7) girls together.....So A is sufficient
Just by seeing Statement II, its clearly visible that its insufficient since without knowing (x,y) values we cannot find the total work done. So options B,D,E,C rules out
OA: (A)
1 girl can do the work in day is 1/24 ...=> for x boys its y/24
From Statement I: the efficiency of boys is twice than that of girls so x/15=2*y/24 also given x+y=27...from both eqns we get values of x,y so that we can get the number of days taken to complete the work by (x – 8) boys and (y – 7) girls together.....So A is sufficient
Just by seeing Statement II, its clearly visible that its insufficient since without knowing (x,y) values we cannot find the total work done. So options B,D,E,C rules out
OA: (A)
