Aptitude - Simple Interest - Discussion

8. 

A lent Rs. 5000 to B for 2 years and Rs. 3000 to C for 4 years on simple interest at the same rate of interest and received Rs. 2200 in all from both of them as interest. The rate of interest per annum is:

[A]. 5%
[B]. 7%
[C].
7 1 %
8
[D]. 10%

Answer: Option D

Explanation:

Let the rate be R% p.a.

Then, 5000 x R x 2 + 3000 x R x 4 = 2200.
100 100

100R + 120R = 2200

R = 2200 = 10.
220

Rate = 10%.


Priya said: (Feb 6, 2011)  
How do you know when to use the right formulas?

Thiru said: (Apr 5, 2011)  
Hey its the formula of CP.

Kuldeep Singh said: (Apr 18, 2011)  
From where this 120R came. Please some one tell me.

Mahesh Kumar Sanka said: (May 26, 2011)  
@Kuldeep Singh

(3000*r*4)/100=120R

once check it out.

@Thiru

This is the formulae of Simple interest only (i=(p*t*r)/100).

Vineesh said: (Sep 12, 2011)  
@priya there is only one formula for simple interest. You can easily use it always just by interchanging terms.

Shrikanth Duppada said: (May 3, 2013)  
Lets assume that rate % = x.

(If you have taken 5000 on 1% then S.I per year = 50 Rs (1 Rs for 100 then 50 hundreds so 50x100(5000)=50 Rs, if 50 per single year so for 2 years it would be 100)(Similarly for 3000).

Then S.I on 5000 for 2 years = 100x.
Then S.I on 3n000 for 4 years = 120x.
From the problem 100x+120x = 2200.

Then 220x = 2200.

x=10.
I hope this is clear.

Saji said: (Oct 17, 2013)  
@Srikanth, very good explanation. I expect such shortcut method from the discussion part keep doing the same.

Arun said: (Nov 21, 2013)  
By Using SI = (PRT/100).

Nishant said: (Jun 22, 2014)  
@Priya.

r*5000*2/100 + r*3000*4/100 = 2200.
And then take L.C.M.
r*10000+r*12000 = 220000.

10000r+12000r = 220000.
22000r = 220000.
r = 220000/22000.
r =10.

Priya Kuldeep said: (Oct 15, 2014)  
@Nishant.

You are doing it in a lengthy manner.

Monica said: (Oct 25, 2015)  
Let's solve through options, take option 10%

Now, First, A to B.

10% of 5000 = 500.

Time = 2 years.

S.I = 500x2 = 1000.....I.

Similarly, 10% of 3000 = 300.

Time = 4 years.

S.I = 300x4 = 1200......II

Adding I and II,

Total S.I = 2200 (as given in question).

Mohit said: (Feb 11, 2016)  
2200/200, 220 how come?

Anand J said: (Apr 11, 2016)  
In question A, B and C are given. I thought there were 3 members, I tried for 3 members. Then what is "A". Is A first person or sentence formation? Please explain.

Likith said: (Aug 20, 2016)  
Guys, it easy.

5000-B-2yrs
3000-c-4yrs.

The rate of interest same(data).
Finally, the lender gets total 2200 as interest. (use some logic).

Assume B pays x amount of interest,
It means c pays x - 2200.

x =(5000 * 2 * R)/100 (B DATA).
X - 2200 = (3000 * 4 * R)/100 *C DATA.

SOLVE ABOVE 2 EQUATIONS, YOU Will GET 10% RATE OF INTEREST.

Kumar said: (Nov 30, 2016)  
5000 * 2 = 10000
3000 * 4 = 12000
------------------------
= 22000

R%= 2200 * 100/22000 * 1 = 10.

Anil said: (Feb 10, 2017)  
Friends use backward method through options
take 10%.

10% of 5000 is 500 (for 1 year)
For 2 years 500*2 = 1000.
10% of 3000 is 300(for 1 year)
For 4 years 300*4 = 1200.

Add both interests 1000+1200 = 2200.

Adil Shaikh said: (Sep 18, 2017)  
Hi,

Thanks everyone for giving such good explanation.

K. Haritha said: (Dec 17, 2017)  
5000*2*r/100+3000*4*r/100=2200,
100r+120r=220r,
220r=2200,
10.

Nagesh N said: (Aug 28, 2018)  
According to %change=(Difference/ initial value)*100.

Similarly (5000-3000)=2000.

((2200-2000)/2000)*100=(200/2000)*100 = 10%.

Francis said: (Nov 7, 2018)  
We subtract 5000-3000=2000.
We get 2000,
In this shows that si 2200 from both,
So 2000*10% = 200+2000 = 2200.
We can understand that 10 % will be the rate of interest.

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