MATH 157 - D100A SSIGNMENT #3
Due date: Wednesday Jan 25, 2012
Instructor Questions accompanying paper Assignment # 3 Solution
Directions: Print double sided, write your solutions to both questions directly on this
page, place immediately after cover page and staple together!
Marks: An answer without a detailed solution process will be awarded zero marks!
Q1: The annual sales of Crimson Drug Store are expected to be given by
S(t) = 2:3 + 0:4t
million dollars t years from now, whereas the annual sales of Cambridge Drug Store are expected to
be given by
S(t) = 1:2 + 0:6t
million dollars t years from now. When will the annual sales of Cambridge ﬁrst surpass the annual
sales of Crimson?
Solution: Set 2:3 + 0:4t = 1:2 + 0:6t. We solve for t and get 1:1 = 0:2t or t = 5:5. When 5 and half years,
the annual sales of Cambridge ﬁrst surpass the annual sales of Crimson.