Question

2.
Dr. Smith wants to do a research on light accuracy and a sum of Rs. 32000 was
invested in a research in two parts. One part was deposited at 8% pa, and the
other part was deposited at 12% p.a. The sum earns an interest of 9% pa Find the
difference (in Rs.) of the two parts.
A 12000
B 14000
C 16000
D 10000​

Answer 1

Answer:

dr samit javh ha v aha hz shs 12000

Answer 2

Answer:

The correct answer is option (c) 16000

Step-by-step explanation:

Given data  

A sum of Rs.32000 was invested in two parts

part one was deposited at 8% per annum

part two was deposited at 12% per annum

the earned interest on total sum per annum = 9%

here we need to find difference between two invested parts

Let x and y be the invested two parts

sum two parts     x + y = 32000 _(1)

from given data interest earned per annum = 9%

interest earned = $\frac{9}{100} (32000)$  

                          = 9 (320)

                          = 2880 Rs.  

now calculate interest on both parts x and y  

interest on x at rate of interest 12% for 1 years  

here  Principal amount (P) = x, Rate (R) = 12% , time (T) = 1 year

           interest   = $\frac{PTR}{100}$  

                          =  $\frac{x(1)(12)}{100}$                                      

                          = $\frac{3x}{25}$  

interest on y at rate of interest 8% for 1 years  

here Principal amount (P) = y , Rate (R) = 8%, time (T) = 1 year

         interest  = $\frac{y(1)(8)}{100}$  

                        = $\frac{2y}{25}$  

from given data interest earned = Rs.2880    which is equals to interest earned on both x and y  

         ⇒   $\frac{3x}{25} + \frac{2y}{25} = 2880$  

         ⇒   $\frac{3x+2y}{25} = 2880$  

         ⇒  3x + 2y = 72000 _(2)

Now solve (1) and (2)  

  3 × (1)  ⇒  3x + 3y = 96000 _(4)

  1 × (2) ⇒   3x +2y = 72000 _(5)

do (4) - (5)

     ⇒    3x + 3y - 3x - 2y = 96000 - 72000

                                     y = 24000 Rs

therefore  x = 32000 - 24000 = 8000

the invested parts x = 8000 and y = 24000

difference between x and y  = 24000 - 8000 = Rs.16000