Question 179659
let x be the cost of the shirt and y be the cost of the tie
:
x=y+15........eq 1
x+y=85........eq 2
:
take  x's value from eq 1 and plug it into eq 2
:
(y+15)+y=85
:
2y=70
:
${{{highlight(y=35)}}}cost of tie
:
${{{highlight(x=35+15=50)}}}cost of shirt