sahil repays the total loan of rupees 2,36,000 by paying every month starting from the first instalment of rupees 2000. he increases the instalment rupees 200 every month. what amount would he pay as the last instalment of loan
Jaizah15:
which class?
Answers
Answered by
7
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
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
Similar questions