Answers

  • qais
  • Content Quality
2016-02-02T23:45:56+05:30
It's like an AP, whose terms are
2000, 2200, 2400, 2600,..... so on
A/q
2000 + 2200 + 2400 + 2600 +.....to n months = 236000
a = 2000
d = 200
sum of n terms= (n/2)(2a +(n-1)d)
236000 =(n/2)(4000 +(n-1)200)
⇒2360 =n(20 +(n-1))
⇒n² +19n - 2360 =0
⇒n² +59n - 40n -2360 =0
⇒n(n +59) -40(n +59) =0
⇒(n+59)(n -40) =0
n =40 or n = -59
n cannot be negative so, n =40
now , 40th term = (2000 +(40 -1)200) = Rs 9800
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