Question

If Ramya needs Rs.900000 after 10 years . how much she should invest now in a bank pays 20% SI?
A) Rs.2,00,000
B) Rs.3,00,000
C) Rs.4,00,000
D) Rs.5,00,000

Answer 1

Answer:300000

Step-by-step explanation:

Investment = x

Interest = 20%

Years = 10

Interest type simple interest

The formula is

X + (X x 20/100 x 10) = 900000

X + (X x 2) = 900000

X + 2X = 900000

3X = 900000

X = 900000 / 3

X = 300000

Answer 2

Given,

Amount = ₹900000,

Time = 10 years,

Rate of simple interest = 20%.

To find,

Principal.

Solution,

The principal amount needed to invest now can be calculated simply by using the relation between the total amount and principal, given below.

$A=P(1+\frac{Rt}{100})$     ...(1)

Where,

A = amount after 't' years,

P = principal,

R = rate of interest (%), and,

t = time (years).

Here,

A = ₹900000,

R = 20%,

t = 10 years.

Substituting the above values in equation (1),

$900000 =P(1+\frac{(20)\cdot (10)}{100} )$

Rearranging and simplifying the above equation,

$P(1+2)=900000$

⇒ $P=\frac{900000}{3}$

⇒ P = ₹300000.

Therefore, the principal amount needed to invest now is ₹3,00,000.