Question

The total number of students ina school increased by 12% this school year compared to the total number of students last school year. If the school has s students this school year, which one of the following expressions showsthe total number of students lastschool year?A: S + 012sB: 1.12sC: S ÷ 112D: S - 0.12s

Answer 1

Explanation

From the statement, we know that:

• the total number of students increased by 12% this year compared to the total number of students last school year,

• S is the total number of students this school year.

We define as L the number f tstudents of last year.

If L increased by 12%, the number of students this school year is:

$S=L+12\%\cdot L=L+\frac{12}{100}\cdot L=L+0.12\cdot L=1.12\cdot L.$

Dividing both sides by 1.12, we get the number of students the last school year was:

$L=\frac{S}{1.12}=S÷1.12.$Answer

C. S ÷ 1.12