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

If + means - , - means ×, × means ÷, and ÷ means +, then what will be the value of following expression?
15 – 2 ÷ 90 × 9 + 10

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 =?

If 'F' means '+', 'P' means '×', 'T' means '÷' and 'K' means '-' then 40 T 8 F 16 P 4 K 13 =?

If 246*2 = 6, 870*3 = 11, then what should 735*5 be?

If 21 (49) 14 and 159 (169) 146, then what is the value of 'A' in 56 (A) 44? 

If - means ÷, + means ×, ÷ means -, × means +, then which of the following equations is correct? 

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 = ?