Find the next number in the series

12, 20, 40, 72, 116, 172 ?

Look at the below sequence of letters and tell us what the next letter should be:

O T T F F S S ?

Solve the following series:
AZ, GT, MN, __, YB

Two guards were on duty outside a barracks. One faced up the road to watch for anyone approaching from the North. The other looked down the road to see if anyone approached from the South. Suddenly one of them said to the other, "Why are you smiling?"

How did he know his companion was smiling?

Thomas has missed an excessive number of days of school, so he must meet with Principal Davis. Mr. Davis asks him "Why on Earth have you missed so many days?" Thomas replies "There just isn't enough time for school. I need 8 hours of sleep a day, which adds up to about 122 days a year. Weekends off is 104 days a year. Summer vacation is about 60 days. If I spend about an hour on each meal, that's 3 hours a day or 45 days a year. I need at least 2 hours of exercise and relaxation time each day to stay physically and mentally fit, adding another 30 days. Add all of that up and you get about 361 days. That only leaves 4 days for school." The principal knows Thomas is full of it, but can't figure out why. Where is Thomas going wrong?

While handling a project, the landscaper is asked by the owner of the mansion that he wants four trees in front of his mansion that are exactly equidistant from each other.

How will he do it?

In which direction should the missing arrow point?

Can you find any error in the following sentence?

A taxi was standing outside a fort at night. A man came out of the fort, opened the gate and hit the taxi driver killing him instantly. He took all the money out of the meter and started running till he was caught by a local sheriff.

In a holy town, three temples sit in a row identical in almost every manner including a holy well in front of them. A pilgrim comes to visit the temples with some flowers in his basket.

At the first temple, he takes some water from the holy well and sprinkles it on the flowers to wash them. To his astonishment, the number of flowers in his basket doubles up. He offers a few of them at the temple and turns back to visit the second temple.

At the second temple, he again takes some water from the holy well and sprinkles it on the flowers to wash them. Again the number of flowers double up in number. He offers some of them at the temple and turns back to visit the third temple.

At the third temple, he repeats the process and the number of flowers doubles up yet again. He offers all the flowers in the third temple.

Now, the pilgrim offered the same number of flowers in all the temples. Can you find out the minimum number of flowers he must have had initially? How many flowers did he offer to god in each of the three temples?

My sock drawer has 26 blue socks, 13 pink socks, 33 green socks, and 12 red socks, how many socks would I have to pull out in the dark to be sure I had a matching pair?