Math Problem Statement

Solve the question

How many numbers are divisible by 8 from 101–200?

Solution

Let's solve the given question:

"How many numbers are divisible by 8 from 101–200?"


Solution:

To determine how many numbers between 101 and 200 are divisible by 8, we follow these steps:

  1. Find the first number divisible by 8 in this range:

    • Start from 101 and check for divisibility by 8.
    • 104104 is the first number divisible by 8 because: 104÷8=13(exactly divisible).104 \div 8 = 13 \, \text{(exactly divisible)}.
  2. Find the last number divisible by 8 in this range:

    • Start from 200 and check for divisibility by 8.
    • 200200 is the last number divisible by 8 because: 200÷8=25(exactly divisible).200 \div 8 = 25 \, \text{(exactly divisible)}.
  3. Count all multiples of 8 between 104 and 200:

    • The multiples of 8 form an arithmetic sequence: 104,112,120,,200104, 112, 120, \dots, 200

      • First term (aa) = 104
      • Last term (ll) = 200
      • Common difference (dd) = 8
    • Use the formula for the nn-th term of an arithmetic sequence: l=a+(n1)dl = a + (n - 1) \cdot d Substituting values: 200=104+(n1)8200 = 104 + (n - 1) \cdot 8 200104=(n1)8200 - 104 = (n - 1) \cdot 8 96=(n1)896 = (n - 1) \cdot 8 n1=12n=13n - 1 = 12 \quad \Rightarrow \quad n = 13


Final Answer:

There are 13 numbers divisible by 8 between 101 and 200.


Correct Option:

B. 13

Would you like a further explanation, or do you have other questions? 😊


Related Questions:

  1. What is the sum of all numbers divisible by 8 between 101 and 200?
  2. How many numbers between 101 and 200 are divisible by both 8 and 4?
  3. What is the greatest common divisor (GCD) of the numbers divisible by 8 in this range?
  4. How many odd numbers are there between 101 and 200?
  5. How many numbers between 101 and 200 are divisible by 3?

Tip:

When solving problems with multiples, always use the formula for an arithmetic sequence to find the total number of terms quickly.

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Math Problem Analysis

Mathematical Concepts

Arithmetic Sequences
Divisibility
Number Theory

Formulas

nth term of an arithmetic sequence: l = a + (n - 1) * d
Divisibility rules for integers

Theorems

Arithmetic Progression Formula

Suitable Grade Level

Grades 6-8