Victor grilled 21 burgers at a block party. He grilled the same number of pounds of turkey as hamburgers. Each turkey burger weighed 1/4 pound and each hamburger weighed 1/3 pound. How many of each did Victor grill?

(1/4)t = (1/3) h

t + h = 21

3 t = 4 h
h = (21 - t)

3 t = 4 (21-t)
3 t = 84 - 4 t
7 t = 84
etc