[tex]23 \times (20 - (624 \div a - 24) \div 5) = 46 \\ 20 - (624 \div a - 24) \div5 = 46 \div 23 \\ 20 - (624\div a - 24) \div 5 = 2 \\ (624 \div a - 24) \div 5 = 20 - 2 \\ (624 \div a - 24) \div 5 = 18 \\ 624 \div a - 24 = 18 \times 5 \\ 624 \div a - 24 = 90 \\ 624 \div a = 90 + 24 \\ 624 \div a = 114 \\ a = 624 \div 114 \\ a = 5.4[/tex]