Who became Ireland's youngest ever Prime Minister in

Select the number from among the given options that can replace the question mark (?) in the following series.

64, 60, 52, 40, ?, 4

Four terms are in proportion. The first, second and fourth terms are 4, 22, and 33. Find the third term.

If 4     x       4           7          15        38.5

Then,  ( x  + 1) ( x  - 1) = ?

6 6 3 6.5 12 33

26 63 124 215 342 511 ?

140     300     380      420      440      ?

10      14       41       ?         182        218

66       187       43       212       ?       241