Coding and Decoding Questions

If 2%1 = 30, 6%2 = 80 and 2%5 = 70, then find the value of 4%1 = ?

If 19!3 = 32, 13!4 = 18 and 12!2 = 20, then find the value of 17!3 = ?

If 7∆6 = 84, 1∆4 = 8 and 2∆3 = 12, then find the value of 8∆4 = ?

If "$" means "added to", "@" means "divided by", "#" means "multiplied by" and "%" means "subtracted from", then

136 @ 17 # 0 $ 19 % 5 = ?

If 40@8 = 50, 30@3 = 100 and 10@2 = 50, then find the value of 20@5 = ?

The following equation is incorrect. Which two signs should be interchanged to correct the equation?

24 + 4 - 20 ÷ 9 x 5 = 31

The following equation is incorrect. Which two signs should be interchanged to correct the equation?

20 + 12 x 35 - 20 ÷ 10 = 31

The following equation is incorrect. Which two signs should be interchanged to correct the equation?

12 - 16 x 25 ÷ 80 + 10 = 7