SarkariPYQ

SSC CPO 2019 PYQ — Question 106

SSC CPO Tier I - 11th December 2019 - Shift 2 • Quantitative Aptitude • Q106

Back to paper

The compound interest amounts on a certain sum at a certain rate percentage p.a. for the second year and third year me `3,300 and `3,630, respectively. What is the amount of the same sum at the same rate in 2½ years, interest compunded yearly?

Show answer & explanation

Correct answer: C

Explanation

The correct answer is Option 3 i.e. 38115

Understanding Application
Tricks
Ratio
1st yr 2nd yr 3rd yr
CI1 3300 3630
  10 11

Since ratio of 2nd yr and 3rd yr = 10 : 11

So

ratio of 1st yr and 2nd yr also be 10 : 11
Here

11 unit = 3300

10 unit = 3300/11 × 10

= 3000 

&

CI3 - CI2 = 11 - 10 = 1

So

R = 10%

So

P = 30000
Now
P = 30000 1st yr 2nd yr 3rd yr
10% 3000 3000 3000
  10% 300 300
      300
    10% 30

Total CI3 = 3000 + 2 × 300 + 30

= 3630

Since we need only 2.5 year

So

For 0.5 year

= 3630/2

= 1815
Hence

after 2.5 yr

= 30000 + 3300 + 1815

= 35115