Question

The table shows the year groups of some students who use the canteen. Mr Ford wants to survey 50 of these students stratified by year group. How many more year 9 students than year 8 students should be in the survey?

Answer 1

7

Explanation:

Answer 2

7 more year 9 students than year 8 students should be surveyed, If Mr.Ford wants to survey 50 of these students stratified by year group.

Explanation:

The given is,

Year Students

7 80

8 110

9 160

Total 350

Mr.Ford wants to survey 50 of these students stratified by year group.

Step:1

Formula to find the ratio of number of grouped students to total students,

`Ratio, r = (Number of students grouped )/(Total number of students)`

=
`(50)/(350)`

= 0.1428

Step:2

Formula for Number of students surveyed from year wise,

For year 7 students,

= (Ratio) × (Students from year 7)

= 0.1428 × 80

= 11.424

≅ 11 (∵ For students we convert into whole number)

For year 8 students,

= (Ratio) × (Students from year 8 )

= 0.1428 × 110

= 15.708

≅ 16 (∵ For students we convert into whole number)

For year 8 students,

= (Ratio) × (Students from year 9 )

= 0.1428 × 160

= 22.8

≅ 23 (∵ For students we convert into whole number)

Step:3

To find How many more year 9 students than year 8 students should be in the survey

= ( Students from year 8 for group) -

( Students from year 8 for group)

= 23 - 16

= 7 students

Result:

7 more year 9 students than year 8 students should be surveyed, If Mr.Ford wants to survey 50 of these students stratified by year group.