A person pays ₹975 by monthly installment each less then the former by ₹5. The first installment is ₹100. The time by which the entire amount will be paid is??
Answers
Answered by
8
a person pays = 975 $ monthly
each less = 5 $
his first installment is =100 $
975 $ _ 100 =875 $
each less = 5 $
his first installment is =100 $
975 $ _ 100 =875 $
AChyuthaGS:
Thank you very much
Answered by
20
Sn= 975. a= 100. d= -5
Sn= n/2[2a+(n-1)d]
975= n/2[2(100)+(n-1)(-5)]
1950= n (200-5n+5)
1950= n(205-5n)
1950= 205n-5n^2
5n^2-205n+1950=0
n^2-41n+390=0
n^2-15n-26n-390=0
(n-15) (n-26)=0
n= 15 months
Similar questions