A six digit number is formed by writing a three digit number two times consecutively. Find the least four digit number which can exactly divide this type of six digit number.

The ratio of the students of one school is 3: 5 with the students of the other school, if in the first school there were 50 students more and in the second there were 80 students less then the ratio would be 5: 6. Find the total number of students in both schools.

The cost price of 60 articles is same as the selling price of x articles. If there is a profit of 20%, then what is the value of x?

Two successive discounts of 40% and 20%, respectively, on the marked price of an article are equal to single discount of Rs 988. The marked price (in Rs) of the article is:

Pipe A can fill a tank in 6 hours. Pipe B can fill the same tank in 10 hours – pipe A, B, C together can fill the same tank in 12 hours. In how many hours pipe C can fill the tank alone?

The factors of  $$ x^2-2x-15 $$ are: 

The HCF and LCM of two numbers are 3 and 2730 respectively. If one of the numbers is 78, find the other number.