36. David invested certain amount in three different schemes A, B and C with the rate of interest 10% p.a., 12% p.a. and 15% p.a. respectively. If the total interest accrued in one year was Rs. 3200 and the amount invested in Scheme C was 150% of the amount invested in Scheme A and 240% of the amount invested in Scheme B, what was the amount invested in Scheme B?

A. Rs 10000 B. Rs 8000 C. Rs 6500 D. Rs 5000

Answer Answer: Option D Explanation: Explanation:-Let x, y and z be the amounts invested in schemes A, B and C respectively. Then,
add individual interest to get total using Si= pxrxt/100
[x x 10 x 1]/100 + [y x 12 x 1]/100 + [z x 15 x 1]/100 = 3200
10x + 12y + 15z = 320000…. (i)Now, z = 240% of y =(12/5)y……… (ii)And, z = 150% of x =(3/2)x so,x=(2/3 )z = (2/3) x value of z from ii
x= (2/3) x (12/5) y = (8/5)y………..(iii)
From (i), (ii) and (iii), we have :
16y + 12y + 36y = 320000
64y = 320000
y = 5000
Sum invested in Scheme B = Rs. 5000

37. A portion of $6600 is invested at a 5% annual return, while the remainder is invested at a 3% annual return. If the annual income from the portion earning a 5% return is twice that of the other portion, what is the total income from the two investments after one year?

A. 200 B. 270 C. 250 D. .270

Answer Answer: Option B Explanation: Explanation – 5x + 3y = z (total)
x + y = 6600
5x= 2(3y) [ condition given] 5x – 6y = 0
x + y = 6600
5x -6y = 0
Subtract both equations and you get x = 3600 so y = 3000
3600*.05 = 180
3000*.03 = 90
z (total) = 270

38. A certain sum is invested for T years. It amounts to Rs. 400 at 10% per annum. But when invested at 4% per annum, it amounts to Rs. 200. Find the time (T)?

A. 50years B. 41 years C. 41years D. 39 years

Answer Answer: Option A Explanation: Explanation –
We have, A1 = Rs. 400, A2 = Rs. 200, R1 = 10%, R2 = 4%
Time (T) = [A1 – A2] x 100 divide by A2R1 – A1R2
= [400 – 200]x 100 divide by [200 x 10 – 400 x 4]= 20000/400 = 50 Years.

39. An automobile financier claims to be lending money at the simple interest, but he includes the interest every six months for calculating the principal. If he is charging an interest of 10%, the effective rate of interest becomes?

A. 10.80% B. 10.10% C. 10.25%% D. 10%

Answer Answer: Option C Explanation: Explanation –
Let the sum be Rs. 100. Then,
S.I. for first 6 months = Rs. [100 x 10 x 1] / [100×2]= Rs. 5.
S.I. for last 6 months = Rs.[105 x 10 x 1] / [100 x 2]= Rs. 5.25
So, amount at the end of 1 year = Rs. (100 + 5 + 5.25) = Rs. 110.25.
Effective rate = (110.25 – 100) = 10.25%.