A teacher has 100 pencils in a cup. 16 are more sharp than dull. How many are dull and how many are sharp?

X = dull pencils

y = sharp pencils

x + y = 100

y = x + 16 ~~Plug this back into your original x+y equation.

x+x+16=100 = = > 2x = 84 = = > x = 42. Plug this back into the y = equation

y = 42 + 16 = = > y = 58.

42 Dull, 58 sharp.