Let's say he gave away x pens and y stickers. He gave away 5000 little advertisements. Therefore, x + y = 5000 The pens each cost 23 cents and the stickers cost 14 cents and he spent 970 dollars, Therefore, 0.23x + 0.14y = 970 We now have simultaneous equations. x + y = 5000 (1) 0.23x + 0.14y = 970 (2) Manipulate (1) x +y = 5000 y = 5000 - x (3) Substitute (3) into (2) 0.23x + 0.14y = 970 0.23x + 0.14(5000-x) = 970 0.23x + 700 - 0.14x = 970 0.09x = 270 x = 270/0.09 = 3000 He gave away 3000 pens. Altogether, he gave away 5000 advertisements. Therefore, he gave away 2000 stickers as well. Hope that helps!