Huilan's age is three times thomas's age. the sum of their ages is 100 . what is thomas's age?

X2 + y 2 = 36 x + y = 6 solve the system of equations.

In a small section of a stadium there are 40 spectators watching a game between the cook islands and fiji. they all support at least one of the two teams. 25 spectators support the cook islands and 16 of these support both teams. how many support only fiji?

Mrs. blake's bill at a restaurant is $42.75. she wants to leave the waiter an 18% tip. how much will she pay in all, including the tip?