Question

A certain principal amounts to Rs. 15000 in 2.5 years and to Rs. 16500 in 4 years at the same rate of interest. Find the rate of interest.

Answer 1

Given:

Amount becomes:

$\implies$ 15000 in 2.5 years

$\implies$ 16500 in 4 years

Simple interest for (4-2.5) years:

$\implies$ 16500 - 15000

Therefore:

SI for 1.5 years = Rs. 1500

SI for 2.5 years:

$\implies$ 1500/1.5 * 2.5

$\implies$ 2500

Principal amount:

$\implies$ 15000 – 2500

$\implies$ Rs. 12500

Rate of Interest:

$\implies$ 2500 * 100 / 12500 * 2.5

$\implies$ 250000 / 31250

$\implies$ R = 8%

Final answer: 8%

Answer 2

Answer

No of Amount

⟹ 15000 of 2.5 years

⟹ 16500 of 4 years

Interest for (4-2.5) years:

⟹ {16500 - 15000}

Hence,

Simple Interest for [1.5 years = Rs. 1500]

Simple Interest for 2.5 years:

⟹( 1500/1.5 and 2.5)

⟹ (2500)

PA(principal amount)

⟹ (15000 – 2500)

⟹ (Rs. 12500)

Rate of Interest:

⟹ (2500 =100 / 12500 = 2.5)

⟹( 250000 / 31250)

⟹( Rate of interest = 8%)

$percentage \: = 8\%$