Question

Totol Amount fo be paid
[
=4000+680=24680
]
Let man pays ( x ) in first month ( x-20 ) in second moth Total sum ( = )
[
begin{aligned}
& x+(x-20)+(x-40)-ldots(x-220)
=&(2 x-20(1+2 ldots 11)
=& 12 x-frac{20 times 11 x^{6} / 2}{x}=4680
end{aligned}
]
( Rightarrow 12 x=6000 )
( Rightarrow x=operatorname{sod}(text { first thatalonort }) ) last is ( (x-220) )
( 0.500-220=(280) ) ansintallment
[
text { Ans } 500,280
]

# A man borrows Rs. 4000 and agrees to repay with a total interest of Rs. 680 in 12 monthly instalments. Each instalment being less than the preceding one by Rs. 20. Find the first instalment and the last instalment. (Ans: a = Rs 500, 1, = Rs 280)

Solution