x weeks = 7x days x days = x days Total = 8x days

The population of rodents in a house doubles every day. Every day 25 rodents are killed. How many rodents are there if after every 4 days, the number of rodents becomes same again?

6 boys can complete writing 6 notebooks in 6 weeks. 4 girls can complete writing 4 notebooks in 4 weeks.

How many notebooks can 12 boys and 12 girls complete in 12 weeks?

When x^9 - x is factorized as completely as possible into polynomials and monomials with integral coefficients, how many factors are there?

How many integer solutions are there to the system of equations below and which are those solutions?

x^2+y-z = 42 x+y^2-z = 18