Loading Maths 1. How much time will it take for an amount of Rs. 900 to yield Rs. 81 as interest at 4.5% per annum of simple interest? A. 2 years B. 3 years C. 1 year D. 4 years

Here is the answer and explanation

Explanation :

P = Rs.900

SI = Rs.81

T = ?

R = 4.5%

$\text{T= }\dfrac{100 ×\text{SI}}{\text{PR}} = \dfrac{100 × 81}{900 × 4.5} = 2 \text{ years}$

 2. Arun took a loan of Rs. 1400 with simple interest for as many years as the rate of interest. If he paid Rs.686 as interest at the end of the loan period, what was the rate of interest? A. 8% B. 6% C. 4% D. 7%

Here is the answer and explanation

Explanation :

Let rate = R%

Then, Time, T = R years

P = Rs.1400

SI = Rs.686

\begin{align}&\text{SI= }\dfrac{\text{PRT}}{100} \\ \\ &\Rightarrow \text{686 = }\dfrac{\text{1400 × R × R}}{100} \\ \\ &\Rightarrow 686 = 14 \text{ R}^2 \\ \\ &\Rightarrow 49 = \text{R}^2 \\ \\ &\Rightarrow \text{R} = 7\end{align}

i.e.,Rate of Interest was 7%

 3. A sum of money at simple interest amounts to Rs. 815 in 3 years and to Rs. 854 in 4 years. The sum is : A. Rs. 700 B. Rs. 690 C. Rs. 650 D. Rs. 698

Here is the answer and explanation

Explanation :

Simple Interest (SI) for 1 year = 854-815 = 39

Simple Interest (SI) for 3 years = 39 × 3 = 117

Principal = 815 - 117 = Rs.698

 4. A sum fetched a total simple interest of Rs. 929.20 at the rate of 8 p.c.p.a. in 5 years. What is the sum? A. Rs. 2323 B. Rs. 1223 C. Rs. 2563 D. Rs. 2353

Here is the answer and explanation

Explanation :

SI = Rs.929.20

P = ?

T = 5 years

R = 8%

$\text{P = }\dfrac{100 \times \text{SI}}{\text{RT}}=\dfrac{100 \times 929.20}{8 \times 5}\text{ = Rs.2323}$

 5. Mr. Thomas invested an amount of Rs. 13,900 divided in two different schemes A and B at the simple interest rate of 14% p.a. and 11% p.a. respectively. If the total amount of simple interest earned in 2 years be Rs. 3508, what was the amount invested in Scheme B? A. Rs. 6400 B. Rs. 7200 C. Rs. 6500 D. Rs. 7500

Here is the answer and explanation

Explanation :

Let the investment in scheme A be Rs.x

and the investment in scheme B be Rs.(13900 - x)

\begin{align}&\text{We know that }\text{SI = }\dfrac{\text{PRT}}{100}\\\\ &\text{Simple Interest for Rs.x in 2 years at 14% p.a. = }\dfrac{x \times 14 \times 2}{100} = \dfrac{28x}{100}\\\\ &\text{Simple Interest for Rs.(13900 - x) in 2 years at 11% p.a. = }\dfrac{(13900 - x) \times 11 \times 2}{100} = \dfrac{22(13900 - x)}{100}\\\\ &\text{Total interest = Rs.3508}\\\\ &\dfrac{28x}{100} + \dfrac{22(13900 - x)}{100} = 3508\\\\ &28x + 305800 -22x = 350800\\\\ &6x = 45000\\\\ &x = \dfrac{45000}{6} = 7500\end{align}

Investment in scheme B = 13900 - 7500 = Rs.6400

1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10

ashwini
2015-03-23 12:45:04
Simple Interest on certain sum at the rate of 10% per annum for 6 years and 7 years differs by rs.650/- what is the sum ? give me answer fast (0) (0) Reply
Dev
2015-04-05 18:37:09
Simple interest for one year = 650

PRT/100 = 650
P * 10 * 1/100 = 650
P = 6500
The sum is Rs.6500 (0) (0) Reply
newwave
2014-12-30 09:23:16
A certain sum of money amounts to Rs.1008 in 2 years and to Rs.1164 in 3.5 years.find the sum and rate of interest. (0) (0) Reply
Bratisankar
2015-01-07 20:44:00
in 3.5 yrs the amount 1164
in 2    yrs the amount 1008 -
___________________________
the 1.5 yrs interest is        156
the 1    yr  interest is   156/1.5  =104
the 2 yrs interest is 208 rs
principal=1008-208=   800
rate of interest=(104/800)*100
=13% (0) (0) Reply
Jay
2015-01-04 19:44:29
Let the amount be P and rate of interest be R%

Simple Interest on P for 2 years = (1008-P)
P * 2 * R/100 = (1008-P)
2PR = 100(1008-P) ----(eq:1)

Simple Interest on P for 3.5 years = (1164-P)
P * 3.5 * R/100 = (1008-P)
3.5PR = 100(1164-P) ----(eq:2)

(eq:1)/(eq:2) 2/3.5 = 100(1008-P)/100(1164-P)
20/35 = (1008-P)/(1164-P)
4/7 = (1008-P)/(1164-P)

4(1164-P) = 7(1008-P)
4656 - 4P = 7056 - 7P
3P = 2400
P = 800

From eq1, 2*800*R = 100(1008-800)
2*800*R = 100*208
R = 13
Rate of Interest is 13% (0) (0) Reply
Suhani
2014-09-24 06:42:15
A alone can complete a work in 16 days and B alone in 12 days. Starting with A,they work on alternate days. The total work will be completed in how many days? please tell answer. (0) (0) Reply
Rajeev
2016-09-10 09:50:26
A-16                - 3
B-12   LCM:48   - 4

A+B 2 days - 7

48/7 = 6
balance: 48-42 = 6
A- 3 (13th day)
B- 3, (3/4 day)

Ans: 13 3/4 days. (0) (0) Reply
Dev
2014-09-30 21:32:13
Work done by A in 1 day is 1/16 and work done by B in 1 day is 1/12

In day 1, only A works and total work gets completed = 1/16
In day 2, only B works and total work gets completed = 1/12
this pattern continues till total work gets completed

Work completed in every 2 days = 1/16 + 1/12 = 7/48
So in 2*6 = 12 days,  6*7/48 = 42/48 = 7/8 work gets completed

in 13th day, total work gets completed = 7/8 + 1/16 = 15/16

Remaining work = 1/16
days taken by B to complete this = (1/16)/(1/12) = 3/4 days

So total work gets completed in 13 3/4 days (0) (0) Reply
Athira
2015-01-07 19:34:21
3w/d--->A---16             (1)

4w/d---->B---12            (2)
.........................
7w/d---->A+B....48w

TOTAL DAYS =13 3/4 days
 A3W B4W A3W B4W A3W B4W A3W B4W A3W B4W A3W B4W A3W B3W (0) (0) Reply
Akshay
2015-09-09 11:25:21
Athira, Couldn't able to understand the equations you made.
Pls explain (0) (0) Reply
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