Question

in which number is the value of the digit 4 equal to 40?
a. 95,247
b. 34,589
c. 23,421
d. 17,524

Explanation:

Step1: Recall place values (tens place: \(10\))

We need the digit 4 to have a value of 40. Since \(4\times10 = 40\), the digit 4 must be in the tens place (second digit from the right).

Step2: Analyze each option

- **Option A: 95,247**
The digit 4 is in the tens place? Let's check positions (from right: 7 (ones), 4 (tens), 2 (hundreds), 5 (thousands), 9 (ten - thousands)). Wait, no: positions (right - to - left: 1 (ones), 2 (tens), 3 (hundreds), 4 (thousands), 5 (ten - thousands)). So in 95,247: digits are 9 (ten - thousands), 5 (thousands), 2 (hundreds), 4 (tens), 7 (ones). Wait, no: 95,247 is 9 (ten - thousands), 5 (thousands), 2 (hundreds), 4 (tens), 7 (ones)? Wait, no, 95,247: \(9\times10000 + 5\times1000+2\times100 + 4\times10+7\times1\). So 4 is in tens place: \(4\times10 = 40\)? Wait, no, let's re - check other options.
- **Option B: 34,589**
Digits: 3 (ten - thousands), 4 (thousands), 5 (hundreds), 8 (tens), 9 (ones). So 4 is in thousands place: \(4\times1000 = 4000 eq40\).
- **Option C: 23,421**
Digits: 2 (ten - thousands), 3 (thousands), 4 (hundreds), 2 (tens), 1 (ones). So 4 is in hundreds place: \(4\times100 = 400 eq40\).
- **Option D: 17,524**
Digits: 1 (ten - thousands), 7 (thousands), 5 (hundreds), 2 (tens), 4 (ones). So 4 is in ones place: \(4\times1 = 4 eq40\).

Wait, I made a mistake earlier. Let's re - do the place values correctly.

For a number \(abcde\) (where \(a\) is ten - thousands, \(b\) is thousands, \(c\) is hundreds, \(d\) is tens, \(e\) is ones):

- **Option A: 95,247** → \(a = 9\) (ten - thousands), \(b = 5\) (thousands), \(c = 2\) (hundreds), \(d = 4\) (tens), \(e = 7\) (ones). So \(d = 4\) (tens place), so value of 4 is \(4\times10=40\). Wait, but let's check again. Wait, no, 95,247: \(9\times10000 + 5\times1000+2\times100 + 4\times10+7\times1=90000 + 5000+200 + 40+7\). So the 4 is in tens place, value \(4\times10 = 40\). Wait, but let's check the other options again.

Wait, no, the correct way:

We need the digit 4 to have a value of 40, which means \(4\times10=40\), so the digit 4 must be in the tens place (the second digit from the right, i.e., the digit in the tens place, which is the 2nd position from the right).

Let's list the numbers with their digit positions (right - most is position 1 (ones), position 2 (tens), position 3 (hundreds), position 4 (thousands), position 5 (ten - thousands)):

- **95,247**: digits (from right: position 1: 7, position 2: 4, position 3: 2, position 4: 5, position 5: 9). So position 2 (tens) has digit 4. So \(4\times10 = 40\).
- **34,589**: from right: position 1: 9, position 2: 8, position 3: 5, position 4: 4, position 5: 3. So position 4 (thousands) has digit 4: \(4\times1000 = 4000\).
- **23,421**: from right: position 1: 1, position 2: 2, position 3: 4, position 4: 3, position 5: 2. So position 3 (hundreds) has digit 4: \(4\times100 = 400\).
- **17,524**: from right: position 1: 4, position 2: 2, position 3: 5, position 4: 7, position 5: 1. So position 1 (ones) has digit 4: \(4\times1 = 4\).

So the number where the digit 4 has a value of 40 is 95,247? Wait, but let's check again. Wait, maybe I messed up the numbering. Let's write each number in expanded form:

- \(95247=9\times10000 + 5\times1000+2\times100 + 4\times10+7\times1\). So the 4 is multiplied by 10, so its value is 40.
- \(34589 = 3\times10000+4\times1000 + 5\times100+8\times10 + 9\times1\). 4 is multiplied by 1000, value 4000.
- \(23421=2\times10000 + 3\times1000+4\times100+2\times10 + 1\times1\). 4 is multiplied by 100, value 400.
- \(17524=1\times10000 + 7\times1000+5\times100+2\times10 + 4\times1\). 4 is multiplied by 1, value 4.

So the correct option is A. 95,247.

Answer:

A. 95,247