Simple & Compound Interest Questions for CAT with Answers PDF

Simple interest = 
Profit earned by Mr. Bajaj = SI received by Mr. Bajaj from Ambani + SI received by Mr. Bajaj from Mittal - SI paid by Mr.Bajaj to the bank
= 1,000 + 2,250 - 3,000
= Rs. 250

Let the principal amount be 'P' and rate be r.
Amount after 5 years = 2P
Simple interest = A - P = 2P - P = P
According to the question,
P = 
r = 20%
Rate = 20%

The problem can be solved by using the formula for simple interest:

We need to put the value of each principle amount at a different rate of interest as each of them is invested for a year:
SI = Rs. 500
So, 
⇒ 50,000 = 20,000 + 14,000 + 2500x
⇒ 16,000 = 2500x
⇒ 
⇒ x = 6.4
This is correct answer. 

Suppose, Rs. x be lent at 6% and Rs. (4000 – x) at 8%.
Then,

6x + 32000 – 8x = 27200
2x = 32000 – 27200 = 4800
x = Rs. 2400
Thus, the two parts are Rs. 2400 and Rs. 1600.
So, required ratio = = 3 : 2

Let P be the principal.
Compound interest for 2 years = P 
Simple interest for 2 years =

Principle amount = Rs. 1500

Let for x years he paid at 7.5%.

⇒ (13,500x - 12,600x) + 2,64,600 = 2,70,900
⇒ 900x = 2,70,900 - 2,64,600
⇒ 900x = 6300

The interest earned per year would be 1500/3=500. This represents a 10% rate of interest.

Let's consider the principal is Rs1400 and rate of interest is 10%.

then after 1st year the interest will be( Rs 1400 × 10% )= Rs140

After completing first year the principal amount will be :-

Principal + rate of interest = Rs ( 1400 + 140) =Rs 1540

In second the principal will be = Rs1540

Rate of interest will be same = 10%

Now after second year the interest will be :-

  1540 × = Rs154

∴ After second year total repaid amount will be:-

=Principal of second year + interest after second year .

=Rs( 1540 + 154) =Rs 1694

Hence option d) matches with the question,

Ans :- Only option (d) matches with the question. there option (d) will be the correct answer.

Interest in 2 years = ₹ 240.
Interest per year = ₹ 120
Rate of interest = 10%

5% for 3 years (SI) = 15% of the amount; At the same time 4% SI for 4 years means 16% of the amount. The difference between the two is 1% of the amount. 1% of 500 = ₹ 5