Rio Olympics were held in  Rio de Janeiro, Brazil, from 5 August to 21 August 2016.

• Athletes : 11303
• Countries : 207
• Events : 306

Sum of ages of husband, wife and child= (24 × 3) + 9 = 81 years

Sum of ages of wife and child => 25 × 2 + 10 = 50 + 10 = 60 years

Age of husband = 81 - 60 = 21 years.

Here given series follows a pattern that

0.25, 8, 128, 1024, ?

0.25 x 32 = 8

8 x 16 = 128

128 x 8 = 1024

1024 x 4 = 4096

Dry ice or Cardice is the solid form of Carbon dioxide.

1. It has an advantage of lower temperature than the water ice and doesn't leave any residue.

2. The reason why it is called as Dry ice is because unlike the normal ice, it won't melt into liquid form. It directly evaporates into the air as gas. That is Solid to gas form passing through liquid state is a phenomenon called as Sublimation.

3. The primary use of dry ice is as cooling agent.