Coding and Decoding Questions

In a certain code language, '-' represents '+', '+' represents 'x', 'x' represents '÷' and '÷' represents '-'. Find out the answer to the following question.

10 + 20 x 10 ÷ 20 - 8 = ?

If + means ÷, ­ means x, x means ­ and ÷ means +, which of the following will be the value of expression 16÷8­4+2x4=?

If 15#2 = 26, 11#3 = 16 and 10#9 = 2, then find the value of 11#4 = ?

If "$" means "addition", "@" means "division", "#" means "multiplication" and "%" means "subtraction", then 84 @ 12 # 3 $ 24 % 35 = ?

If 70$7 = -10, 50$5 = -10 and 40$8 = -5, then find the value of 10$2 = ?

If 'WZB' stands for 'DAY', how will you code 'MONDAY'?

If "*" denotes "added to", "&" denotes "divided by", "@" denotes "multiplied by" and "%" denotes "subtracted from", then 136 & 8 @ 7 % 3 * 7 = ?

If the code for MOTHER is JRQKBU then what is the code for PRINCIPAL?