If 3x + (1/3x) = 9 then find 27x³ + (1/27x³ ) =

28.11 × 3.98 + 29.03 × 3.12 – 34.95 + 95.9 × 4.02 =?

1279.98 ÷ 40.48 × 10.12 = ? × 2.16

10562.41 - 7893.78 + 9647.35 + ? = 19500.24

? = (5.8)² + (8.9)² + (4.7) ² + 24.7% of 20

19.22 × 11.99 + 142.15 = ?

(`sqrt(224.95)` `xx` `sqrt(440.89)` ) + (`sqrt(783.82)` `xx` `sqrt(440.87)` ) = ? + 150.03% of 120.33 - 139.86% of 1249.88

40.93√? + √6625 + √6920 + √? = 205.7542`xx` 7.654

? + 151.99 – 100.01 = 23.01 × 4.98

What will come in place of the question mark (?) in the following series?

50, 25, 25, ?, 75, 187.5