Answer: He sold 200 Kansas City Chief T-shirts.
Step-by-step explanation:
Let x represent the number of Kansas City Chief T-shirts that John sold.
Let y represent the number of San Francisco 49er T-shirts that John sold.
He sold 250 shirts altogether. This means that
x + y = 250- - - - - - - - - - -- - -1
John sold 4 times as many Kansas City Chief T-shirts as San Francisco 49er T-shirts. This means that
x = 4y
Substituting x = 4y into equation 1, it becomes
4y + y = 250
5y = 250
y = 250/5 = 50
x = 4y = 4 × 50
x = 200
