Assume that the price of the T-shirt is x and the price of the tie is y.
Fashion Phreddy buys 5 shirts and 3 ties for 91. This means that:
5x + 3y = 91 .........> equation I
5x = 91-3y
x = 18.2 - (3/5) y ..........> equation II
Billy joe bob buys 8 shirts and 5 ties for 146. This means that:
8x + 5y = 146 ...........> equation III
Substitute with equation II in equation III:
8(18.2 - (3/5) y) + 5y = 146
145.6 - 4.8y + 5y = 146
0.2y = 0.4
y = 2
Substitute in equation II to get the value of x:
x = 18.2 - (3/5) (2) = 17
Based on the above calculations:
price of T-shirt = x = 17
price of tie = y = 2