Question

Less than half of the students missed the chemistry demonstration. In fact only 3/10 of the students missed the demonstration. If 21 students did not miss the demonstration, how many students did miss the demonstration?

Answer 1

9 students missed the demonstration

Explanation:

The given is that `3/10` mussed the demonstration and 21 students were present during the demonstration.

Since we know that `3/10` of the students missed the demonstration, therefore `7/10` were present. So let `x` be the number of students in the whole class, since `7/10` of the class attended the demonstration, we can denote it in equation form by,

`7/10 x = 21`

Solving for `x`,

`7/10 x = 21`
`7x = 210`
`x = 30`

So there are a total of 30 students in the class. Using this value, we will able to solve for the number of students who missed the demonstration.

total no. students who missed the demonstration`= 3/10 (30) = 9`