Multiple choice general knowledge math & puzzles

At the McDuffy Middle School, there are 80 students in Grade 7. Of these students, 34% have brown hair and 61% have black hair. The rest of the students have red hair. How many students have red hair?

  1. 2

  2. 4

  3. 5

  4. 6
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Calculate the percentage of students with red hair: 100% - 34% (brown) - 61% (black) = 5%. Then find 5% of 80 students: 0.05 × 80 = 4 students. This is a straightforward percentage calculation problem.

AI explanation

To solve this problem, we need to find the percentage of students with red hair.

Given:

  • Total number of students in Grade 7: 80
  • Percentage of students with brown hair: 34%
  • Percentage of students with black hair: 61%

To find the percentage of students with red hair, we subtract the sum of the percentages of students with brown and black hair from 100%:

Percentage of students with red hair = 100% - (Percentage of students with brown hair + Percentage of students with black hair)

Percentage of students with red hair = 100% - (34% + 61%)

Percentage of students with red hair = 100% - 95%

Percentage of students with red hair = 5%

To find the actual number of students with red hair, we can calculate 5% of the total number of students:

Number of students with red hair = 5% of 80

Number of students with red hair = (5/100) * 80

Number of students with red hair = 4

Therefore, the correct answer is B) 4.

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