Can you solve this tricky maths equation problem by replacing it? mark with the correct symbol?

19834 -----: 187
15921 -----: 153
17561 -----: 139
13734 -----: ???

In 1990, a person is 15 years old. In 1995, that same person is 10 years old. How can this be?

A clock loses 10 minutes each hour. If the clock is set correctly at noon, what time is it when it reads 3 PM?

I look at you, you look at me I raise my right, you raise your left. What am I?

Two natural numbers have a sum of less than 100 and are greater than one.

John knows the product of the numbers and Jacob knows the sum of numbers.

The following conversation takes place between them:
John: 'I am not aware of those numbers.'
Jacob: 'I knew you wouldn't be. I am not aware myself.'
John: 'Now I know them!'
Jacob: 'Now I know them, too!'

What are the two numbers?

I am looking for a word that change both gender and number when i add the letter 'S'.

What Word am I Looking For ?

In the given figure, move three matchsticks so that the resulting figure contains two rectangles.

A man always keeps a spare tyre in his car. To make full use of all the five tyres, he changes the tyres in a manner that for a distance of 1, 00,000 km, each of them runs the same distance.

Can you calculate the distance travelled by each tyre on that journey?

What is the largest amount of money that you can possess in change and still if someone asks you for a dollar, you won't be able to give?

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