Development of embryo from antipodal cell is known

If '+' means '÷', '-' means ' X ', ' X ' means '+', '÷' means '-', what will come in place of the question mark(?)?

If, 'A $ B' means 'A + B', 'A & B' means 'A ÷ B', 'A % B' means 'A X B' and 'A # B' means 'A - B', then what is the value of the given equation?

If four hats are picked at random, what is the probability that one is green, two are blue and one is red?

Which two signs should be interchanged to make the given equation correct?

8 – 42 + 15 × 20 ÷ 4 = 346

  If $ means +, # means - , @ means x and * means ÷, then what is the value of 22 $ 3 @ 10 # 21 * 7 =?

If + means ÷, × means –, – means ×,  ÷ means +, then 32 + 16 – 13 x 18 ÷ 2 = ?