Question

A sum of rs 1,780 becomes rs 2,136 in 4 years. Find
( i)the rate of interest.
(ii) the sum that will become rs 810 in 7 years at the same rate of interest​

Answer 1

Answer:

Solution:

(i)In first case, Principal (P) = Rs. 1780

Amount (A) = Rs. 2136

∴ SI = A - P = 2136 - 1780 = Rs. 356

Time(T) = 4 years

∴ Rate =

\frac{SI\times100}{P\times T}=\frac{356\times100}{1780\times4}=5\%\ p.a

P×T

SI×100

=

1780×4

356×100

=5% p.a

(ii) In second case, Let principal (P) = Rs. 100

Rate (R) = 5% p.a , Time (T) = 7 years

∴ SI = \frac{PRT}{100}=\frac{100\times7\times5}{100}=Rs.35

100

PRT

=

100

100×7×5

=Rs.35

∴ Amount = P + SI = Rs. 100 + 35 = Rs. 135

If amount is Rs. 135, then principal = Rs. 100

And if the amount is Rs. 810, then principal = Rs.\frac{100\times810}{135}=Rs.600Rs.

135

100×810

=Rs.600

Hope its help..

Answer 2

Answer:

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