Elitmus
Exam
Numerical Ability
Averages
of the 4 nos,whose average is 60,the first one is 1/4th of the sum of the sum of the last 3.the first no is what?
Read Solution (Total 9)
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- Let four number be p q r and s, then p+q+r+s = 240 and It is also given that p=1/4(q+r+s). So on combining equation numbers 1 and 2. We get p=48
- 7 years agoHelpfull: Yes(6) No(0)
- (a+b+c+d)/4=60
a+b+c+d=240;
a=1/4(b+c+d)
b+c+d=4a;
substitute value of b+c+d in equation
a+4a=240;
5a=240;
a=48 - 7 years agoHelpfull: Yes(3) No(0)
- the sum of the last three is 48 so 1/4th is 12
- 7 years agoHelpfull: Yes(1) No(2)
- let a,b,c,d be numbers
their avg is 60 i.e (a+b+c+d)/4=60 -----eq 1
also a=1/4*(b+c+d) -----eq 2
i.e b+c+d =4a
substituting in eq 1
a+4a=4*60
5a=240
a=48
thus first number is 48 - 7 years agoHelpfull: Yes(1) No(0)
- (q+r+s)/4 +q+r+s=240
5(q+r+s)=960
q+r+s=192
so, (q+r+s)/4=48 - 7 years agoHelpfull: Yes(0) No(0)
- Let First No=x
Let sum of rest 3 no's = y
(x+y)/4=60
x+y=240.....(A)
also it is given that 4x=y
therefore,
4x+x=240
5x=240
x=48 - 7 years agoHelpfull: Yes(0) No(0)
- a=0.25(240+a)
=> a=58 - 7 years agoHelpfull: Yes(0) No(0)
- A + B + C + D = 240.
NOW A = B + C + D/4
B + C + D + 4B + 4C + 4D =960
5 (B + C + D ) = 960
B + C + D = 192
SINCE A IS 1/4 (B + C + D) SO WE GET 48 (192/4). - 7 years agoHelpfull: Yes(0) No(0)
- given (a+b+c+d)/4=60
therefore, a+b+c+d=240
now given
a=1/4of(b+c+d)
therfore,we can also write a+b+c+d=240 as,
1/4(b+c+d)+(b+c+d)=240
{(b+c+d)+4(b+c+d)}/4=240
5(b+c+d)=240*4
b+c+d=240*4/5
b+c+d=192
now a= 1/4 of (b+c+d)
a=1/4*192
ie, 48 ans. - 7 years agoHelpfull: Yes(0) No(0)
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