Four years ago, Luke was one quarter of his brother's age. In two years time, if Luke's age is doubled it will equal his brothers age. How old is Luke now?

Are triangles the congruent? write the congruency statement.what is the congruency that proves they are congruent? what is the perimeter of ∆pqr?

Two airplanes start at the same place and travel in opposite directions,one at 395 miles per hour and the other at 422 miles per hour. how many hours will it take for the planes to be 2451 miles apart?

The sum of 5consecutive even numbers is 100. what is the first number in this sequence?