Replace the question mark with the number below given a simple math problem.

Andrew’s doctor gives him three pills and tells him to take one every half hour. How much time will have passed by the time Andrew’s taken all three pills?

The square root of number 121 is "11". What is the square root of the number "12345678987654321."?

When I get multiplied by any number, the sum of the figures in the product is always me. What am I?

You walk into a room and see a bed. On the bed, there are two dogs, five cats, a giraffe, six cows, and a goose. There are also three doves flying above the bed. How many legs are on the floor?

I drive at an average speed of 30 miles per hour to the railroad station each morning and catch my train. On a particular morning, there was a lot of traffic and at the halfway point, I had averaged only 15 miles per hour. How fast must I drive for the rest of the way to catch my train?

I speak without a mouth, and hear without ears. I have no-body, but I come alive with the wind. What am I?

What word begins and ends with an E, but has only one letter?

You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?

Replace the question mark with the correct number in below Picture: