What value should come in place of the question mark (?) in the following question?

52x14+145018=1998÷?

Alarms from 3 different clocks sound after every 2, 4 and 6 hours, respectively. If the clocks are startedat the same 6 time, how many times do the alarms ring together in 3 days?

(−12)[11+7×(−3)]÷{}[413−(−3)×(−6)]=

An object travels 24 m in 3 s and then another 15 m in 2 s. What is the average speed of the object?

An object travels 24 m in 3 s and then another 15 m in 2 s. What is the average speed of the object?

Vishal is 20 years younger to Arya. Twelve years hence Arya's age will be 1.25 times that of Vishal. Aryais now ......... years old.

In the following question, select the missing number from the given series.1 108, 81, 54, 27, ?

Z’s present age is 55 years. If 11 years ago, C’s age was 1/11 of Z’s age, then after how many years C’s age will become 37 years?

In the following question, select the missing number from the given series.
 
1912, 2012, 2133, 2277, 2446, ?