The simple interest on a certain sum is one-fifth of the…

The simple interest on a certain sum is one-fifth of the sum, and the interest rate percent per annum is 3.2 times the number of years. If the rate of interest increases by 4%, then the simple interest (in ₹) on ₹7,500 for 4 years is:

Show answer & explanation

Correct answer: C

Explanation

The correct answer is Option 3 i.e. 3,600.

SI = $PRT\over100$

According to the question,

⇒ ${1\over5}P$ = $P\times3.2T\times T\over100$

⇒ ${1\over5}$ = $3.2T^2\over100$

⇒ 3.2T² = 20

⇒ T² = 6.25

⇒ T = 2.5

Rate = 3.2 × 2.5 = 8%

New Rate = 8 + 4 = 12%

SI = ${7500\times12\times4}\over100$ = 75 × 48 = ₹3600

SSC Selection Post 2024 PYQ — Question 53