Q. In a triangle A is the greatest angle ana A+7B=155 then what will be the range of c

• Answer 30 < c < 85
  Solution:
  A+7B=155 ..........(1)
  A+B+C=180 ..........(2)
  from (1) & (2)
  6B-25=C ........(3)
  now try the least possible value of B and the max value of B and get the range of C.
  for example:
  clearly put B=1 you will get C=31 hence C should be greater than 30.
  Now put B=10 , u will get C=85 but B+C=95 hence A=85 but it is given A is greatest.
  So C should be less than 85. :)
• 11 years agoHelpfull: Yes(34) No(22)
• Ans
  
  79>c>31
• 11 years agoHelpfull: Yes(8) No(3)
• Given
  
  a + 7 b=155
  
  and a is greatest
  
  that means
  
  a = 92 85 78 71 64 57 50 43
  
  b = 63 70 77 84 91 98 105 112
  
  after dividing b by 7
  
  b = 9 10 11 12 12 14 15 16
  
  then
  
  when a=78 and b = 11 then range of c is 91
  
  when a = 85 and b =10 then range of c is 85
  
  Above two cases cant be possible then
  
  when we take a=92 b=9 then c=79 which is acceptable...........
  
• 9 years agoHelpfull: Yes(3) No(0)
• 85>c>25
  explaination : the triangle is isoceles , sum of the angles is 180
• 11 years agoHelpfull: Yes(2) No(9)
• http://www.careerbless.com/qna/discuss.php?questionid=915
• 7 years agoHelpfull: Yes(1) No(0)
• arnab can u explain in detail
• 11 years agoHelpfull: Yes(0) No(3)
• any body written the exam this option is theire or no
  
• 11 years agoHelpfull: Yes(0) No(1)
• I had a dobuet let it be 84 then the possible combinations be (85,11),(86,10),87,9).......... like which doesn't satisfies A+B=155,and A+B+C=180 at a time
• 11 years agoHelpfull: Yes(0) No(1)
• 25
• 11 years agoHelpfull: Yes(0) No(0)
• and MIRZA what if you put B= 1/6
• 11 years agoHelpfull: Yes(0) No(0)
• 25
• 11 years agoHelpfull: Yes(0) No(0)
• if you put c=25 you will get B=0 hence c>25 if you put c=85 you will get A=85 not a valid angle as A is largest of all hence c
• 11 years agoHelpfull: Yes(0) No(1)
• A+B+C=180
  A must be >=90
  B+C
• 10 years agoHelpfull: Yes(0) No(0)
• Answer: 25 < C < 85
  
  Explanation
  
  A + 7B = 155 ---(1)
  A + B + C = 180 ---(2)
  A>B ---(3)
  A>C ---(4)
  
  From (1)
  B =
  155
  −
  A
  7
  155−A7
  
  Substituting the value of B in (2)
  A +
  (
  155
  −
  A
  )
  7
  (155−A)7 + C = 180
  7A + 155 - A + 7C = 1260
  6A + 7C = 1105
  => C =
  (
  1105
  −
  6
  A
  )
  7
  ⋯
  (
  5
  )
  (1105−6A)7⋯(5)
  
  Above equation represent C in terms of A. From this equation, we can see
  a. C gets maximum value when A is lowest.
  b. C gets minimum value when A is highest.
  
  Find minimum and maximum values of A subject to A>B and A>C which when substituted in the above equation gives possible range of C.
  
  From (1), A can be close to 155 when B is near zero.
  i.e., the highest value A can take is close to 155 (with A < 155)
  
  if A = 155, C =
  (
  1105
  −
  6
  ×
  155
  )
  7
  (1105−6×155)7 = 25
  Therefore, C > 25 ---(6)
  
  From (1) we have A + 7B = 155. Let B=A. The equation becomes 8A=155 => A = 19.375.
  For A > 19.375, A will be greater than B ---(7)
  
  From (2) we have, C =
  (
  1105
  −
  6
  A
  )
  7
  (1105−6A)7. Let C=A.
  The equation becomes A =
  (
  1105
  −
  6
  A
  )
  7
  (1105−6A)7
  =>13A = 1105
  => A = 85
  i.e., For A > 85, A will be greater than C ---(8)
  
  Since A is the largest, from (7) and (8),we can see that minimum value of A close to 85 (with A > 85)
  
  if A = 85, C =
  (
  1105
  −
  6
  ×
  85
  )
  7
  (1105−6×85)7 = 85
  Therefore, C < 85 ---(9)
  
  Combining (6) and (9)
  i.e., 25 < C < 85
• 7 years agoHelpfull: Yes(0) No(0)