Stock market 2

For the week of July 22, the forecaster recorded the following day-to-day changes in the stock market of a specific stock: -2 on Monday; +4 Tuesday; -8 Wednesday; + 2 1/2 Thursday; - 3 1/4 Friday. The stock began the week at 78 points. How many points did it finish with at the end of the week?

Correct answer:

a₅ =  68.75

Step-by-step explanation:

$$\begin{gathered} a_0=78 \\ {a}_1=a_0-2=78-2=76 \\ {a}_2=a_1+4=76+4=80 \\ {a}_3=a_2-8=80-8=72 \\ {a}_4=a_3+(2+\frac{1}{2})=72+(2+\frac{1}{2})=\frac{149}{2}=74\frac{1}{2}=74.5 \\ {a}_5=a_3-(3+\frac{1}{4})=72-(3+\frac{1}{4})=\frac{275}{4}=68\frac{3}{4}=68.75 \end{gathered}$$

Try another example