Anwers:
1.B
2.B
3.A
4.A
5.B
6.B
7.C
8.C
9.C
10.B
11.C
12.A
13.A
14.A
15.C
Explanation
1.S.I. for 1 year = Rs. (854 - 815) = Rs. 39.
S.I. for 3 years = Rs.(39 x 3) = Rs. 117.
Principal = Rs. (815 - 117) = Rs. 698.
2.Sum = (100× S.I.)/ r × t
= (100 × 4016.25)/ 9 × 5 = Rs. 8925
3.S.I. for 3 years = Rs. (12005 - 9800) = Rs. 2205.
S.I. for 5 years= Rs. 3675
Principal = Rs. (9800 - 3675) = Rs. 6125
Hence Rate = {(100 × 3675) / 6125 × 5} % = 12 %
4.Gain in 2 years = Rs. [{(5000×6.25×2)/100} – {(5000×4×2)/100}]
= Rs. (625- 400) = Rs. 225.
So gain in 1 year = Rs.225/ 2 = Rs. 112.50
5.Principal = Rs. {(100× 5400)/ (12×3)} = Rs.15000.
6.Time =(100×81)/ (450×4.5) years = 4 years
7.Let rate = r% and time = r years
Then (1200×r×r)/100= 432
12 r^2= 432
r=6 %
8.Let the rate be r% p.a.
Then,(5000 x r x 2)/100+(3000 x r x 4)/100 = 2200.
100R + 120R = 2200
R =2200/220= 10.
Rate = 10%.
9.Amount = Rs. [1600×(1+ 5/200)^2 + 1600 × (1+5/200)]
= Rs. 3321
So CI = Amount- Principal
= Rs. 3321 – Rs. 3200 = Rs. 121
10.Amount = Rs. (30000 + 4347) = Rs. 34347,
Let the time be n years then
30000(1+7/100) ^n = 34347
(107/100) ^n = 34347/30000
So n= 2 year.
11.Let rate r % per annum
1200× (1+r/100) ^ 2 = 1348.32
(1+r/100) ^ 2 = 1348.32/1200
1+r/100 = 106 / 100
r= 6 %
12.SI =Rs. (1200 ×10×1)/100= Rs. 120
CI = Rs.[ 1200×(1+5/100) ^2 - 1200] = Rs.123
So CI-SI = Rs. 3
13.P(1+20/100) ^n > 2P
(6/5)^ n >2
(6/5×6/5×6/5×6/5)>2
so n = 4 years
14.Amount= Rs. 25000(1+12/100)^3= 35123.20
So CI= Rs. (35123.20 - 25000) = Rs. 10123.20
15.C.I.= Rs. 4000(1+10/100)^2 – 40
= Rs. 840
Sum= Rs. (420 × 100)/(3×8) = Rs. 1750
05:30 PM, 16-Dec-2017