Question

A man earns rs. 24,000 pm. he spends 1/3rd of his income on personal expenditures. half of the remaining income is invested in a scheme at 15% interest pa. after investing, half of what is left is invested in a scheme which gives 10% interest pa. the remaining lies in a bank, where it earns an interest of 4% pa. the effective rate of interest earned by the man on his investments at the end of the year is

Answer 1

Ans = 22/3 %

24000
personal expenditure = 8000

investment in scheme of Interest rate 15%
(24000-8000)/2=8000

investment in scheme of Interest rate 10%
(24000-8000-8000)/2=4000

investment in bank
(24000-8000)/2=4000

(15/100)*8000 =1200 ....(1)
(10/100)*4000= 400 ...(2)
(4/100)*400= 160 ....(3)

adding 1,2 and 3 we get the total interest of 1760

rate = (1760/24000)*100= 22/3 %

Answer 2

ANS

11%

STEP BY STEP EXPLANATION

Remaining amount :

A= 24000-24000/3

A=16000

1. 16000/2=8000

SI=PNR /100

=8000*15*1/100

=1200

2. 8000/2=4000

SI=4000*10*1/100

=400

3. 4000

SI=4000*4*1/100

=160

Sum of Total Interest=1200+400+160

=1760

SI=PNR/100

1760=16000*R*1/100

1760/160 = R

Solving this R=11%