SSC Selection Post 2020 PYQ — Question 58

SSC Selection Post - Matriculation Level - 9 Nov 2020 - Shift 3 • Quantitative Aptitude • Q58

The compound interest on a certain sum for 1 year at 8% p.a., interest compounded half-yearly, is ₹652.80. What will be the simple interest on the same sum for 2121\over2years at the same rate of interest?

Show answer & explanation

Correct answer: D

Explanation

The correct answer is option 4 i.e. ₹1,600.

 

R = 82=4%\frac{8}{2} = 4\%  per half-year

n = 2

CI=P(1+r100)n−P=P[(1+4100)2−1]CI = P \left(1 + \frac{r}{100}\right)^n - P = P \left[ \left(1 + \frac{4}{100} \right)^2 - 1 \right]

CI=P[(1.04)2−1]=P(1.0816−1)=P⋅0.0816CI = P \left[ (1.04)^2 - 1 \right] = P(1.0816 - 1) = P \cdot 0.0816

CI=652.80=P⋅0.0816⇒P=652.800.0816=₹8000CI = 652.80 = P \cdot 0.0816 \Rightarrow P = \frac{652.80}{0.0816} = ₹8000

SI=P⋅R⋅T100=8000⋅8⋅2.5100SI = \frac{P \cdot R \cdot T}{100} = \frac{8000 \cdot 8 \cdot 2.5}{100}

SI=160000100=₹1600SI = \frac{160000}{100} = ₹1600