Coding and Decoding Questions

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

If -2@-4 = -8, -1@-8 = -8 and -1@6 = 6, then find the value of -1@7 = ?

If WORK = 7935, ROCK = 3587 and WART = 1945, which digit stands for T?

If ' + ' means minus , ' - ' means multiplication , ' ÷ ' means plus , and ' x ' means division , then 15 - 3 + 10 x 5 ÷ 5

In a certain code language, '+' represents 'x', '-' represents '+', 'x' represents '÷' and '÷' represents '-'. What is the answer to the following question?

9 + 3 - 72 x 6 ÷ 3 = ?

If 8*2 = 3, 14*18 = -2 and 18*2 = 8, then find the value of 14*10 = ?

If 80&10 = -8, 50&2 = -25 and 80&16 = -5, then find the value of 20&5 = ?

If mathematical operators '-' and '/' are interchanged, then the value of 15 x 4 ÷ 15 - 11 x 33 ÷ 98 is