In a certain code language, '-' represents 'x', '÷' represents '+', '+' represents '÷' and 'x' represents '-'. Find out the answer to the following question.
15 - 6 + 10 x 3 ÷ 2 = ?

Some equations are solved on the basis of a certain system. Find the correct answer for the unsolved equation on that basis.
33 * 11 * 3 * 6 = 115 

Some equations are solved on the basis of a certain system. Find the correct answer for the unsolved equation on that basis.
7– 4 – 1 = 714, 9 – 2 – 3 = 932 8– 0–4 = ?  

In each of the following questions, which one of the four interchanges in signs and numbers would make the given equation correct?
( 3÷4 ) + 2=2 

Which of the following interchange of signs would make the given equation correct?
6000 + 400 x 300 - 900 ÷ 300 = 3900

If 25 @ 12 @4=296 and 15@6@3=87, then what is the value of 20@8@7=?

In the following question, by using which mathematical operators will the expression become correct?
15 3_4_20 

If 17 × 5=12, 15 ÷ 3=18, 12 + 3 =4 and 6 – 4 -24, then what is the value of 144 + 8 ÷ 64 × 15 – 3 =?