Question

kaylee found out the sizes of all the clubs at her school.
club sizes (number of members)
stem | leaf
1 | 7 8
2 | 0 2 4 4 5 5 6 8
3 | 1 3 6 9 9
4 | 1 3 3 3 6 9
how many clubs have at least 10 members but fewer than 40 members?
□ clubs
submit

Explanation:

Step1: Analyze stem 1

Stem 1 represents numbers from 10 - 19. The leaves are 7, 8, so 2 clubs. But wait, "at least 10" – stem 1: numbers are 17, 18 (since stem is tens place, leaf is ones). Wait, actually, stem - leaf plot: stem is tens digit, leaf is ones. So stem 1: 17, 18 (but we need at least 10? Wait, 17 and 18 are more than 10? Wait, no: "at least 10" means ≥10, "fewer than 40" means <40. So stems 1, 2, 3 (since stem 4 is 40 - 49, which is ≥40, so exclude stem 4).

Wait, stem 1: numbers are 17, 18 (but 17 and 18 are ≥10? Wait, 10 is the lower bound. Wait, stem 1: tens digit 1, so numbers 10 - 19. But leaves are 7,8, so 17,18. Wait, but maybe I misread. Wait, the problem is "at least 10" (≥10) and "fewer than 40" (<40). So numbers from 10 up to 39 (inclusive? No, fewer than 40, so <40, so up to 39). So stems:

• Stem 1: numbers 10 - 19. Leaves: 7,8 → 17,18. Wait, but 10 - 19: the stem is 1, so the numbers are 10 + leaf. Wait, maybe the stem is the tens place, so stem 1: 10 - 19, stem 2: 20 - 29, stem 3: 30 - 39, stem 4: 40 - 49.

So "at least 10" (≥10) and "fewer than 40" (<40) → numbers from 10 to 39 (inclusive? Wait, fewer than 40 is <40, so 39 is included, 40 is excluded). So stems 1, 2, 3.

Now count the number of leaves in stem 1, stem 2, stem 3.

Stem 1: leaves are 7,8 → 2 clubs (17,18)
Stem 2: leaves are 0,2,4,4,5,5,6,8 → 8 clubs (20,22,24,24,25,25,26,28)
Stem 3: leaves are 1,3,6,9,9 → 5 clubs (31,33,36,39,39)

Now sum them: 2 + 8 + 5 = 15? Wait, wait, wait. Wait, stem 1: is 17 and 18 ≥10? Yes, 17 ≥10, 18 ≥10. But wait, maybe the stem 1 is 10 - 19, but the leaves are 7 and 8, so 17 and 18. But maybe I made a mistake. Wait, let's re - check:

Wait, "at least 10" means ≥10, "fewer than 40" means <40. So numbers from 10 to 39.

Stem 1: tens digit 1, so numbers 10 - 19. The leaves are 7,8 → so 17,18. Wait, but 10 - 19: the minimum number here is 17? Wait, no, maybe the stem - leaf plot is written as stem (tens) and leaf (ones), so for stem 1, the numbers are 10 + 7 = 17, 10 + 8 = 18. So two numbers.

Stem 2: tens digit 2, so numbers 20 - 29. Leaves: 0,2,4,4,5,5,6,8. So 20,22,24,24,25,25,26,28. That's 8 numbers.

Stem 3: tens digit 3, so numbers 30 - 39. Leaves: 1,3,6,9,9. So 31,33,36,39,39. That's 5 numbers.

Now sum: 2 (stem 1) + 8 (stem 2) + 5 (stem 3) = 15? Wait, but wait, maybe stem 1 is 10 - 19, but maybe the problem considers "at least 10" as including 10? But in the stem - leaf plot, stem 1 has leaves 7 and 8, so there is no 10, 11, etc. So the numbers in stem 1 are 17 and 18, which are ≥10.

Wait, let's count again:

Stem 1: number of leaves = 2

Stem 2: number of leaves = 8 (0,2,4,4,5,5,6,8 → 8 leaves)

Stem 3: number of leaves = 5 (1,3,6,9,9 → 5 leaves)

Total: 2 + 8 + 5 = 15.

Wait, but maybe I misinterpreted the stem - leaf plot. Let's check the stem - leaf plot structure:

Stem | Leaf

1 | 7 8 → numbers: 17, 18

2 | 0 2 4 4 5 5 6 8 → numbers: 20,22,24,24,25,25,26,28 (8 numbers)

3 | 1 3 6 9 9 → numbers: 31,33,36,39,39 (5 numbers)

4 | 1 3 3 3 6 9 → numbers: 41,43,43,43,46,49 (excluded since <40 is required)

So "at least 10" (≥10) and "fewer than 40" (<40) → numbers from 10 to 39. So we take stem 1, stem 2, stem 3.

Stem 1: 2 numbers (17,18)

Stem 2: 8 numbers

Stem 3: 5 numbers

Total: 2 + 8 + 5 = 15.

Step2: Sum the counts

Sum the number of clubs from stem 1, stem 2, and stem 3.

Number of clubs from stem 1: 2

Number of clubs from stem 2: 8

Number of clubs from stem 3: 5

Total = 2 + 8 + 5 = 15

Answer:

15