NCERT Solutions
Class 10 - Mathematics - Chapter 5: ARITHMETIC PROGRESSIONS - Exercise 5.2
Question 14

Question. 14

How many multiples of 4 lie between 10 and 250?

Answer:

60

Detailed Answer with Explanation:

Step 1: Identify the first and last multiples of 4 in the given range.

Numbers strictly between 10 and 250.

The first multiple of 4 greater than 10 is:

\[12\]

The last multiple of 4 less than 250 is:

\[248\]

Step 2: Recognize this forms an AP of multiples of 4.

AP: \(12, 16, 20, 24, \ldots, 248\)

First term \(a = 12\), common difference \(d = 4\).

Step 3: Use the nth-term formula to find how many terms.

General term of AP:

\[a_n = a + (n - 1)d\]

Here, the nth term equals 248:

\[248 = 12 + (n - 1)4\]

Subtract 12:

\[236 = 4(n - 1)\]

Divide by 4:

\[59 = n - 1\]

So,

\[n = 60\]

Conclusion: There are 60 multiples of 4 between 10 and 250.

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