What has to be broken before you can use it?

Can you find the next number in the below sequence
3 , 7 , 10 , 11 , 12 , 17 ?

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

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

Two boys were admitted to a school. When the headmaster asks them about their parents, they tell him that they have same parents (father and mother). On further inquiry, it turns out that they both share the same date for their birthday.

"Are you twins," ask the headmaster.
"No," replies the boys.

Is it possible?

As you can see that fifteen matches have been used to form an arrangement. What you have to do is remove any six of them to make them ten.

Find the missing letter in the last circle logically in the given below picture.

Find the number of squares in the below-given picture.

I am white when I am dirty, and black when I am clean. What am I?

I have two sand hourglasses:
1. A 7 minute one and
2. An 11-minute one.

Using just these 2 sand hourglasses, how can I measure time as 15 minutes?

Can you count the number of triangles inside a triangle?