Welcome to Westonci.ca, your go-to destination for finding answers to all your questions. Join our expert community today! Our platform connects you with professionals ready to provide precise answers to all your questions in various areas of expertise. Our platform offers a seamless experience for finding reliable answers from a network of knowledgeable professionals.

Daniel decided he wants to run a 5K race. He is starting by running 1 3/4 km and adding 1/2 km each day. How many days will it take him to reach his goal?

Sagot :

If he starts running 1 3/4 km the initial day, and then adding 1/2 km each day, we can model this as a linear function.

The first day he rans 1 3/4 km.

[tex]1+\frac{3}{4}=\frac{4}{4}+\frac{3}{4}=\frac{7}{4}[/tex]

The second day he will run 1/2 km more, so this will be 1 3/4 + 1/2:

[tex]\frac{7}{4}+\frac{1}{2}=\frac{7}{4}+\frac{2}{4}=\frac{9}{4}[/tex]

The n-th day he will run:

[tex]\frac{7}{4}+(n-1)\cdot\frac{1}{2}=\frac{7}{4}+\frac{1}{2}n-\frac{1}{2}=\frac{7}{4}+\frac{1}{2}n-\frac{2}{4}=\frac{5}{4}+\frac{1}{2}n[/tex]

NOTE: n is the index of the day: Day 1 corresponds to n=1, Day 2 correspond to n=2 and so on.

So we have to find at which day he reaches 5 km:

[tex]\begin{gathered} D=5=\frac{5}{4}+\frac{1}{2}n \\ 5=\frac{5}{4}+\frac{2}{4}n \\ 5\cdot4=5+2n \\ 20=5+2n \\ 20-5=2n \\ 15=2n \\ n=\frac{15}{2} \\ n=7.5\approx8\longrightarrow\text{ Day 8} \end{gathered}[/tex]

Answer: he will reach the goal at Day 8.