Kai calculates that he spends 15% of a school day in science class. If he spends 75 minutes in science class, how many minutes does Kai spend in school?



Answer :

luana
[tex]x-minutes\ in\ school\\15\%=0.15\\100\%=1\\\\From\ proportion:\\\\75\ \ \ -\ \ \ 0.15\\x\ \ \ \ \ -\ \ \ 1\\\\0.15x=75\ \ \ |:0.15\\x=500\\\\He\ spends\ 500\ minutes\ in\ school.[/tex]

Answer-

Kai spends 8 hours 20 minutes in school.

Solution-

Let us assume, Kai spends x minutes in school.

Kai calculates that he spends 15% of a school day in science class and that is 75 minutes, i.e

[tex]\Rightarrow x\times \dfrac{15}{100}=75[/tex]

[tex]\Rightarrow x=75\times \dfrac{100}{15}[/tex]

[tex]\Rightarrow x=\dfrac{7500}{15}[/tex]

[tex]\Rightarrow x=500\ \text{minutes}[/tex]

[tex]\Rightarrow x=\dfrac{500}{60}\ \text{hours}[/tex]

[tex]\Rightarrow x=\dfrac{25}{3}\ \text{hours}[/tex]

[tex]\Rightarrow x=8\dfrac{1}{3}\ \text{hours}[/tex]

Therefore, Kai spends 8 hours 20 minutes in school.