Question

A person pays loan of Rs 3900 in a monthly installments each installments being less than the former by Rs 20 and the amount of first installments is Rs 400. In how many installments will the entire amount be paid

Answer 1

Answer:

i hope this is helpful for you

Answer 2

Answer:

n = 15 or 26

Step-by-step explanation:

this que belongs to airthmatic progression

• An arithmetic progression or arithmetic sequence is a sequence of numbers such that the difference between the consecutive terms is constant

GIVEN :

a = 400 i.e first AP

d= -20 i.e difference btw 2 AP

Sn = sum = n/2 { 2a + ( n - 1) d } = 3900

find : n = ?

Sn = n/2 { 2×400 - 20 (n - 1 ) }

3900 = n /2 { 800 - 20n + 20 }

3900 ×2 = 820n - 20n^2

7800 = 820 n - 20n ^2

on solving we get

n^2-41n+390 =o

n^2 -15n -26n +390

n( n- 15 ) -26 ( n - 15 )

( n -15) ( n -26 )

n= 15 or 26.