There are some friends, all less than 20 years. When paired amongst themselves they realize that the sum of their ages is a multiple of 5. If their ages are distinct prime numbers, then the number of possible pairs are: 

Find the solution of 5x-7=12? 

If the LCM of two numbers is 288 and their ratio is 4 : 9, then HCF of the numbers is : 

The sum of the two - digit number is 6 and the number and its flip (digits written in reverse order) both are multiples of 3. If the difference between them is 36, then which of the following is the required number and its flip? 

In a group of 35 people, 23 of them like coffee, 24 of them like tea and each person likes at least one of the drinks. How many like both? 

If the clock is at 3:17, what time will be seen in the mirror?

A mixture of milk and water contains 75% milk. If 8 liters of the mixture is taken out and 7 liters of milk is added, the ratio of milk to water becomes 7 : 2. Find the volume of the initial mixture.

If three cubes of sides 3 cm, 4.5 m and 5 cm respectively are melted to form a big money, then find the side of the new cube.