Arabella invests \( \$ 120 \) at \( 10 \% \) p.a. How long will it take her to earn \( \$ 48 \) in simple interest?

The formula for simple interest is \( I=P r t \), where \( P= \) principal, \( r= \) rate, and \( t= \) time. Solve the formula for \( r \). \( \begin{array}{l} r=\frac{t I}{P} \\ r=\frac{P t}{l} \\ r=\frac{P I}{t} \\ r=\frac{l}{P t}\end{array} \)

If \( x \) represents the number of items produced, (a) write a cost function, (b) find a revenue function if each item sells for the price given, (c) state the profit function, (d) determine analytically how many items must be produced before a profit is realized (assume whole numbers of items), and (e) support the results of part (d) graphically. The fixed cost is \( \$ 500 \), the cost to produce an item is \( \$ 20 \), and the selling price of the item is \( \$ 45 \). (a) The cost function is \( \mathrm{C}(\mathrm{x})=\square \). (Simplify your answer. Do not factor.) (b) The revenue function is \( \mathrm{R}(\mathrm{x})=\square \). (Simplify your answer. Do not factor.) (c) The profit function is \( \mathrm{P}(\mathrm{x})=\square \). (Simplify your answer. Do not factor.) (d) At least \( \square \) items must be produced before a profit is shown. (Type a whole number.) (e) Choose the correct graph to the right.

posited \( \$ 3400 \) into a savings account \( 0.2 \% \). Find the amount in the savings

Who can save money to buy a house?

4) Modélisation du bénéfice : Soit \( b \) la fonction définie sur \( [1 ; 5,5] \) par : \( \quad b(x)=a(x)-c(x) \). a) Que représente \( b(x) \) ? b) Calculer et simplifier \( b(x) \). c) Pour quels prix de vente unitaire d'un séjour l'agence réalisera-t-elle un bénéfice ? On pourra utiliser la calculatrice graphique pour répondre à cette question.