Question

₹890 becomes ₹1068 in 4 years at simple interest.what amount will become ₹1620 in 7 years at the same rate of interest?

Answer 1

Principal= 890

Amount=1068

Time=4years

S.I.=Amount-Principal=1068-890=178

By formula,

S.I.=(P*R*T)/100

178=(890*R*4)/100

(178*100)/3560=R

⇒R=5%

Now,

Principal=1620

Time=7

Rate=5%

SI=P*R*T/100

SI=1620*5*7/100

⇒SI=567

Amount=SI+Principal

⇒Amount=567+1620=2187

Hope you like my answer.

Answer 2

Given :

Principle (P) = Rs. 890          

Time (T) = 4 years

Rate (R) = ?

To Find :

The amount that will become ₹1620 in 7 years at the same rate of interest.

Solution :

Simple Interest (SI) = (1068 - 890)

                         SI  = Rs. 178

We know,  SI = $\frac{P X R X T }{100}$

or,           178  = $\frac{890 X R X 4}{100}$

or,            R    = $\frac{17800}{3560}$

∴             R    =  5%

Now, Let the amount be 'x' that will become ₹1620 in 7 years at the same rate of interest (R).

Simple Interest (SI) = $\frac{P X R X T }{100}$

or,      1620 - x         = $\frac{x X 5 X 7}{100}$

or,      1620 - x         = $\frac{35x}{100}$

or,       1620             = $\frac{135x}{100}$

or,             x             =  $\frac{162000}{135}$

∴               x             =  1200

∴  The amount that will become ₹1620 in 7 years at 5% rate of interest is Rs 1200.