Question

manish borrowed 4000rs and agrees to repay with a total interest of 500rs in 10 instalments each instalment being less than the preceding instalments by 10rs .what should be the first and the last instalments​

Answer 1

Step-by-step explanation:

first = 4500/10=450

• last=4500-(9*10)/10
• (4500-90)/10
• 4190/10
• 419

Answer 2

ANSWER:-

Given:

Manish borrowed Rs.4000 and agrees to repay with a total interest of Rs.500 in 10 installment being less than the preceding installments by Rs.10.

To find:

What should be the first and the last installments.

Solution:

Each installment is Rs.10 less than the preceding one.

Therefore,

The installments are in A.P. with common difference= -10

Manish repays Rs.4000 with interest of Rs.500 in 10 installments.

=)S10= 4000+ 500

=)S10= Rs.4500

Here,

⏺️n= 10

⏺️d= -10

⏺️S10= 4500

In first Installment;

${}^{s} n = \frac{n}{2} [2a + (n - 1)d]\\ \\ = > {}^{s} 10 = 4500 = \frac{10}{2} [2a + (10 - 1)( - 10)] \\ \\ = > 4500 = 5[2a + 9 \times ( - 10)] \\ \\ = > \frac{4500}{5} = (2a + 9 \times ( - 10)) \\ \\ = > 900 = (2a - 90) \\ \\ = > 900 = 2a - 90 \\ \\ = > 2a = 900 + 90 \\ \\ = > 2a = 990 \\ \\ = > a = \frac{990}{2} \\ \\ = > a = Rs.495$

tn= last installment;

${}^{t} n = a + (n - 1)d \\ \\ = > {}^{t} 10= 495 + (10 - 1) \times ( - 10) \\ \\ = > {}^{t} 10 = 495 + 9 \times ( - 10) \\ \\ = > {}^{t} 10 = 495 - 90 \\ \\ = > {}^{t} 10 = Rs.405$

Hence,

The first installment is Rs.495 and the last installment is Rs.405.

Hope it helps ☺️