Math Problem Statement

how many integers are there between 35 and 500 which are divisible by 7

Solution

To find how many integers between 35 and 500 are divisible by 7, follow these steps:

  1. Identify the smallest multiple of 7 greater than or equal to 35:

    Smallest multiple of 735:357=5(exact, so 35 is a multiple of 7)\text{Smallest multiple of 7} \geq 35: \quad \frac{35}{7} = 5 \quad \text{(exact, so 35 is a multiple of 7)}

    Thus, the smallest multiple is 35.

  2. Identify the largest multiple of 7 less than or equal to 500:

    Largest multiple of 7500:500771.4286\text{Largest multiple of 7} \leq 500: \quad \frac{500}{7} \approx 71.4286

    So, the largest multiple is 7×71=4977 \times 71 = 497.

  3. Calculate the number of multiples of 7 between 35 and 497:

    The sequence of numbers divisible by 7 between 35 and 497 is an arithmetic sequence with the first term a1=35a_1 = 35 and the common difference d=7d = 7.

    The nn-th term of the sequence can be represented by: an=a1+(n1)×da_n = a_1 + (n-1) \times d Setting an=497a_n = 497, we get: 497=35+(n1)×7497 = 35 + (n-1) \times 7 Solving for nn: 49735=(n1)×7497 - 35 = (n-1) \times 7 462=(n1)×7462 = (n-1) \times 7 n1=4627=66n-1 = \frac{462}{7} = 66 n=67n = 67

Thus, there are 67 integers between 35 and 500 that are divisible by 7.

Would you like any more details or explanations?

Here are five related questions you might find interesting:

  1. How many integers between 50 and 1000 are divisible by 5?
  2. What is the sum of all integers between 1 and 100 that are divisible by 3?
  3. How many even integers are there between 200 and 600?
  4. What is the smallest positive integer divisible by both 7 and 9?
  5. How many integers between 1 and 1000 are divisible by both 3 and 5?

Tip: To quickly determine how many numbers in a range are divisible by a specific number, consider the smallest and largest multiples of the divisor within the range and calculate how many terms exist in that sequence.

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Math Problem Analysis

Mathematical Concepts

Arithmetic Sequences
Divisibility

Formulas

Arithmetic sequence formula: a_n = a_1 + (n-1) * d

Theorems

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Suitable Grade Level

Grades 6-8