Question

1). Nand Lal borrowed 1000 from his friend on simple interest at 6% per annum. After 7 years, he
paid * 700 cash and a buffalo. What was the cost of buffalo?

explain step by step

2). A sum of money doubles itself in 6 years. In how many years will it treble itself at the same rate of
simple interest ?


explain step by step

3). Ashok invested 2000 for 3 years. He also invested * 1600 for the same period but at a rate of 2%
higher than the first. If the total interest received by him is 996, find the two rates of interest.

explain step by step​

Answer 1

Answer:

1). 720 2).12yrs

Step-by-step explanation:

1). P=1000, R=6%, T=7yr

S.I= P×R×T/100

1000×6×7/100= 42000/100= 420

Now, S.I=420 or P= 1000

A=(P+S.I)= 420+1000= 1420

Therefore, Amount =1420 or money paid back Rs- 700.

Let's the buffalo cost = y

y+700=1420

y=1420-700

y=720

Hence,the cost of buffalo is Rs- 720.

2). Let's sum of money =Rs- y, A=2y, and T=6yr

A=P+S.I

so S.I=A-P= 2y-y = y

S.I=Rs- y, P=Rs- y, A=2y and T= 6yr

Rate =S.I×100/P×T= y×100/y×6yr =16.66%

Then P=Rs-y, A=3y, R=16.66%

S.I=A-P= 3y-y= 2y

T=?

T=S.I×100/P×R =2y×100/ y×16.66%= 12yrs Approx.

Hence,T=12yrs

Sorry, 3rd I don't know.