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

15     18    16   19     17    20    ?

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

 15     12    17  10     ?    8    21     6 

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

15     ?    24    33     97    122     

National Critical Information Infrastructure Protection Centre (NCIIPC) under NTRO assessment states that India's critical sectors may fall prey to inimical forces that could use relaxations in geofencing restrictions granted to employees working from home to make cyber attacks. When was National Technical Research Organisation set up?

India is set to produce indigenous rapid testing and RT-PCR diagnostic kits by the end of which month?

Moody's Investors Service cuts India growth forecast for calendar year 2020 to how much percent from 2.5% projected in March?

Central Public Works Department (CPWD) has issued guidelines on using the central air-conditioners in public buildings during the COVID-19 pandemic. CPWD was established in which year?

The total global military expenditure rose by how much percent to $1,917 billion in 2019?