What will be the ratio of simple interest earned by certain amount at the same rate for $4$ years and $12$ years?

What is the ratio of simple interest earned on certain amount at the rate of $12\%$ p.a. for $9$ years and that for $12$ years ? 

1. $1:2$
2. $2:3$
3. $3:4$
4.$4:5$

What will be the simple interest on a sum of Rs. 10000 after 3 years at the rate of 7.3% per annum? 

(A) Rs. 2,190 

(B) Rs. 2,19,000 

(C) Rs. 2,200 

(D) Rs. 2,180 

A sum of $₹ 2500$ becomes $₹ 8100$ in $2$ years at a certain rate of compound interest. What will be the sum (in $₹$) after $4$ years?

On a certain principal, simple interest amounts to Rs. 1000 in 1 year at the rate of 10% p.a. What will be the effective rate of interest if the same is compounded on a half-yearly basis?

1. 10.10
2. 10.15
3. 10.20
4. 10.25

Kamal’s salary in 2011 was Rs. 30000 per annum. If his salary increases by 5% per annum, what was his salary in the year 2013? 

(A) Rs. 34,728.75 

(B) Rs. 35,000 

(C) Rs. 31,500 

(D) Rs. 33,075