Question

Ramesh borrowed from Suresh certain sum for 2 years at simple interest
He lent this sum to Dinesh at the same rate for 2 years compound interest
At the end of 2 years Ramesh received 110 as compound interest from Dinesh but paid only 100 for simple interest .find rate and sum​

Answer 1

swer:

rate =20 percent

principal=250 rupees

Step-by-step explanation

Ramesh borrowed from suresh certain sum for a 2 years at a simple insterst

ramesh lent this sum to dinesh  at the same rate for 2 years at compound insterst

then  ramesh received the compound interest from dinesh after 2 years 110 rupees

And then paid to suresh 100 rupees  as a simple interst after 2 years

Assume,

principal=P

rate=r

time=t

formula of simple interst is $\frac{prt}{100}$

formula of compound interst is, $P[(1+\frac{r}{100})^n-1]$

SO,

 apees to suresh for 2 years

so for  the first year simple interst is 50 rupees

and second year simple interst is 50 rupees

because in simple interst each year have a same interst

and compound interst and simple interst of first year will be same 50 rupees but in compound interst each year of interst is different

so, difference of  second year in simple interst and compound interst will be 10 rupees

simple interst s·i

compound c·i

formula to find a rate interst  ≈ difference of s·i and c·i for second year ×100÷interst of s·i

r=10×100÷50

r=20 percent

so , by the formula of simple interst

s·i =p×r×t÷100

50=p×20×1÷100

principal= 250 rupees