ANSWER:
Water melon takes 3 seconds to reach the ground from the tenth story of a building.
SOLUTION:
Given, a watermelon is dropped from the tenth story of a building.
We have to solve the equation −16[tex]t^2[/tex] + 144 = 0 for t to find the number of seconds it takes the watermelon to reach the ground.
Now consider the given equation, [tex]-16 t^{2}+144=0[/tex]
[tex]\begin{array}{l}{144=16 t^{2}} \\\\ {t^{2}=\frac{144}{16}} \\\\ {t^{2}=\frac{12^{2}}{4^{2}}} \\\\ {t^{2}=\left(\frac{12}{4}\right)^{2}} \\\\ {t=\frac{12}{4}=3}\end{array}[/tex]
Hence, water melon takes 3 seconds to reach the ground from the tenth story of a building.