10. The half-life of a radioactive substance is 15 years.
Write an equation that can be used to determine
the amount, s(t), of 200 grams of this substance
that remains after t years. (2 points)
Determine algebraically, to the nearest year, how
long it will take for 1/10 of this substance to
remain. (3 points)

Aclothing store has the sign shown in the shop window. pani sees the sign and wants to buy 3 shirts and 2 pairs of jeans. the cost of each shirt before the discount is $12, and the cost of each pair of jeans is $19 before the discount. write and simplify an expression to find the amount pani pays if a $3 discount is applied to her total