Question

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 1

`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.`

Answer 2

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

`\Rightarrow x* (15)/(100)=75`

`\Rightarrow x=75* (100)/(15)`

`\Rightarrow x=(7500)/(15)`

`\Rightarrow x=500\ \text{minutes}`

`\Rightarrow x=(500)/(60)\ \text{hours}`

`\Rightarrow x=(25)/(3)\ \text{hours}`

`\Rightarrow x=8(1)/(3)\ \text{hours}`

Therefore, Kai spends 8 hours 20 minutes in school.