Rajendra got first class certificate with 67.8 % in an examination of 500 marks (5 subjects & 100 ma

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20 Jan 2016 Marks in subject

Rajendra got first class certificate with 67.8 % in an examination of 500 marks (5 subjects & 100 marks for each subject). If he got perfect square marks in all the subjects, then what are the number of possible methods for taking these marks in all the subjects.

OPtion

1) 28
2) 20
3) 4
4) 120
5) 15
6) 12
7) 30
8) 60
9) 32
10)243

Solution

The possible combination of marks is 49, 64, 64, 81, 81 Total number of methods for providing
81 marks for any 2 subjects out of 5 subjects is 10, then number of methods for providing
64 marks for any 2 subjects out of remaining 3 subjects is 3, then 49 marks is provided
for the last subject. Hence total number of methods are 10*3*1 = 30
Option 7)

Correct Option: 7 Best Solution (9)

RAKESH   8 years AGO

339-49= 290
2*145 = 2*(81+64)

5!/2*2 = 30

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SHUBHAM   8 years AGO

took this combination... 64,64,81,81,49... So 5!/2!*2! = 30... 

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DEBMALYA GHOSAL   8 years AGO

numbers are 49, 64, 64, 81, 81
500*67.8%=339
49+64+64+81+81=339
number of possible ways are 5P5/2P2*2P2=30

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priya sunupu   8 years AGO

((64+64+81+81+49)/500)*100=67.8%
So, no. of possible methods =120/(2!*2!)=30

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The Trojan   8 years AGO

the numbers are 64, 81, 49
so 64 has 2 choices out of 5 subjects..i e. 5*4
81 has 2 choices out of 3 subjects i.e 3*2
so total combination=5*4*3*2
repated choices so (5*4*3*2)/(2*2)= 30

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Jaikumar Bhatia   8 years AGO

67.8% of 500 marks=339marks
perfect square marks in all subjects
=49,64,64,81,81=339marks
No of possible methods for taking these marks in all subjects
=5!(2!*2!)=120/4=30
Ans is 30
option is (7)

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JANARTHANAN RAM   8 years AGO

67.8% of 500 =339
All are perfect square,We get two combination
100+100+81+49+9=339 & 81+81+64+64+49=339
We neglect the 1st one because there is 9 mark(he passed in 1st class)
we take second one 81+81+64+64+49=339
total combination will be 5!/2!2!=30
so option 7 will be the ans.

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MRITUNJAY   8 years AGO

possible number is 81 81 64 64 49

possible way is 5!/2!*2!=30
option 7

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vamsi krishna   8 years AGO

67.8% of 500 marks=339 marks
Perfect square marks in all subjects
=49+64+64+81+81=339 marks
No of possible methods for taking these marks in all subjects
=5!(2!*2!)=120/4=30

Like? Yes (1) | No