Question

the students in a seaside school are to have extra swimming lessons if they cannot swim. the table below gives information about the students in grades 7, 8, and 9. complete the table and then answer the questions below.

	can swim	cannot swim	total
grade 8	168	11	type your
grade 9	172	3	type your
total	type your ans	type your ans	type your

how many students need swimming lessons? type your answer...
how many students are in 8th grade? type your answer...
how many 7th grade students cannot swim? type your answer...
how many students in grade 7 and 8 can swim? type your answer...
what is the relative frequency of students who are in 8th grade and cannot swim? round to the nearest percent type your answer...
what is the relative frequency of students who are in 9th grade and can swim? round to the nearest percent type your answer...
what percentage of students cannot swim? round to the nearest percent type your answer...
what percentage of students are 9th graders? round to the nearest percent type your answer...

Explanation:

Step1: Calculate total for each grade

• Grade 7: \(120 + 60 = 180\)
• Grade 8: \(168 + 11 = 179\)
• Grade 9: \(172 + 3 = 175\)

Step2: Calculate total for "Can swim"

\(120 + 168 + 172 = 460\)

Step3: Calculate total for "Cannot swim"

\(60 + 11 + 3 = 74\)

Step4: Calculate grand total

\(460 + 74 = 534\) (or \(180 + 179 + 175 = 534\))

Step5: Students needing swimming lessons (cannot swim)

Sum of "Cannot swim" column: \(60 + 11 + 3 = 74\)

Step6: 8th grade total

From Step1: \(168 + 11 = 179\)

Step7: 7th grade cannot swim

From table: \(60\)

Step8: Grade 7 and 8 can swim

\(120 + 168 = 288\)

Step9: Relative frequency (8th grade, cannot swim)

\(\frac{11}{534} \approx 0.0206 \approx 2\%\)

Step10: Relative frequency (9th grade, can swim)

\(\frac{172}{534} \approx 0.3221 \approx 32\%\)

Step11: Percentage cannot swim

\(\frac{74}{534} \approx 0.1386 \approx 14\%\)

Step12: Percentage 9th graders

\(\frac{175}{534} \approx 0.3277 \approx 33\%\)

Answer:

s (sub-questions):

1. Students needing swimming lessons: \(74\)
2. 8th grade students: \(179\)
3. 7th grade cannot swim: \(60\)
4. Grade 7 and 8 can swim: \(288\)
5. 8th grade, cannot swim (relative frequency): \(2\%\)
6. 9th grade, can swim (relative frequency): \(32\%\)
7. Percentage cannot swim: \(14\%\)
8. Percentage 9th graders: \(33\%\)