Wells Fargo Simple and Compound Interest Problems with Solutions Quiz-1

Answer: Option B
Solution:
S.P of 20 articles = Rs. 60,
Gain = 20%
C.P of 20 articles = Rs. (100/120 × 60) = Rs. 50
Rs. 50, he bought = 20 articles
Rs. 60, he bought = (20/50 × 60) = 24 articles

Answer: Option B

Solution : Time period of 3 years and 6 months means for 3 years, the interest is compounded yearly and for the remaining 6 months, the interest is compounded compounded half yearly. This means that we have 3 cycles of interest compounded yearly and 1 cycle of interest compounded half yearly.
So, Amount = P [1 + (R / 100)]3 [1 + ( {R/2} / 100 )]
=> Amount = 10000 [1 + 0.1]3 [1 + 0.05]
=> Amount = 10000 (1.1)3 (1.05)
=> Amount = Rs. 13975.50
=> Compound Interest, CI = Amount – Principal = 13975.50 – 10000
Therefore, CI = Rs. 3975.50

Solution : Here, P = 5000, A = 5832, n = 2
A = P [1 + (R / 100)]n
=> 5832 = 5000 [1 + (R / 100)]2
=> [1 + (R / 100)]2 = 5832 / 5000
=> [1 + (R / 100)]2 = 11664 / 10000
=> [1 + (R / 100)] = 108 / 100
=> R / 100 = 8 / 100
=> R = 8 %
Thus, the required rate of interest per annum in 8 %

Solution : Let the sum be P.
R = 10 %
n = 2 years
SI = P x R x n / 100 = P x 10 x 2 / 100 = 0.20 P
CI = A – P = P [1 + (R / 100)]n – P = 0.21 P
Now, it is given that CI – SI = 549
=> 0.21 P – 0.20 P = 549
=> 0.01 P = 549
=> P = 54900
Therefore, the required sum of money is Rs. 54,900

Solution : Let the first brother be given Rs. P
=> Money with second brother = Rs. 1000 – P
Now, according to the question,
P [1 + (5 / 100)]4 = (1000 – P) [1 + (5 / 100)]6
=> P (1.05)4 = (1000 – P) (1.05)6
=> 0.9070 P = 1000 – P
=> 1.9070 P = 1000
=> P = 524.38
Therefore, share of first brother = Rs. 524.38
Share of second brother = Rs. 475.62

Solution : Let the sum of money be Rs. P
=> P [1 + (R/100)]3= 669 and P [1 + (R/100)]6= 1003.50
Dividing both equations, we get
[1 + (R/100)]3 = 1003.50 / 669 = 1.50
Now, we put this value in the equation P [1 + (R/100)]3= 669
=> P x 1.50 = 669
=> P = 446

Solution : it is given that the investment doubles itself in 15 years.
Let the initial investment be Rs. P
=> At the end of 15 years, A = 2 P
Now, this 2 P will be invested.
=> Amount after 15 more years = 2 x 2 P = 4 P
Now, this 4 P will be invested.
=> Amount after 15 more years = 2 x 4 P = 8 P
Thus, the investment (P) will become 8 times (8 P) in 15 + 15 + 15 = 45 years