Round these numbers to the nearest tens: 28, 32, 52, 41, 39, 48, 64, 59, 99, 215, 1453, 2936 and fill in the blank _____ with the rounded-off numbers respectively.

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25, 30, 50, 40, 35, 50, 60, 60, 100, 220, 1450, 2940.

30, 30, 55, 40, 40, 50, 60, 60, 100, 220, 1450, 2940.

30, 30, 50, 40, 40, 50, 60, 60, 100, 220, 1450, 2940.

None of these

answer is C.

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Detailed Solution

Concept- Round these numbers to the nearest tens: 28, 32, 52, 41, 39, 48, 64, 59, 99, 215, 1453, 2936 is 30, 30, 50, 40, 40, 50, 60, 60, 100, 220, 1450, 2940.
Thumb Rule of round the numbers to the nearest tens:
If the digit in the One’s position is 5 or more than 5, then the digit in the Ten’s position is increased by 1.
If the digit in the One’s position is less than 5, then the digit in the Ten’s position remains the same.
And in both the above cases, the Digit in the One’s place is replaced with a 0.
For 28, the Ones Place digit is 8 and Tens place digit is 2.
Since 8 is greater than 5, the digit in Ten’s place will be increased by 1 i.e., (2+1=3) and the digit in the One’s place is replaced with a 0.
So, 28 is rounded-off to 30.
For 32, the Ones Place digit is 2 and Tens place digit is 3.
Since 2 is less than 5, the digit in Ten’s place will remain the same, and the digit in the One’s place is replaced with a 0.
So, 32 is rounded-off to 30.
For 52, the Ones Place digit is 2 and Tens place digit is 5.
Since 2 is less than 5, the digit in Ten’s place will remain the same, and the digit in the One’s place is replaced with a 0.
So, 52 is rounded-off to 50.
For 41, the Ones Place digit is 1 and Tens place digit is 4.
Since 1 is less than 5, the digit in Ten’s place will remain the same, and the digit in the One’s place is replaced with a 0.
So, 41 is rounded-off to 40.
For 39, the Ones Place digit is 9 and Tens place digit is 3.
Since 9 is greater than 5, the digit in Ten’s place will be increased by 1 i.e., (3+1=4) and the digit in the One’s place is replaced with a 0.
So, 39 is rounded-off to 40.
For 48, the Ones Place digit is 8 and Tens place digit is 4.
Since 8 is greater than 5, the digit in Ten’s place will be increased by 1 i.e., (4+1=5) and the digit in the One’s place is replaced with a 0.
So, 48 is rounded-off to 50.
For 64, the Ones Place digit is 4 and Tens place digit is 6.
Since 4 is less than 5, the digit in Ten’s place will remain the same, and the digit in the One’s place is replaced with a 0.
So, 64 is rounded-off to 60.
For 59, the Ones Place digit is 9 and Tens place digit is 5.
Since 9 is greater than 5, the digit in Ten’s place will be increased by 1 i.e., (5+1=6) and the digit in the One’s place is replaced with a 0.
So, 59 is rounded-off to 60.
For 99, the Ones Place digit is 9 and Tens place digit is 9.
Since 9 is greater than 5, the digit in Ten’s place will be increased by 1 i.e., (9+1=10) and the digit in the One’s place is replaced with a 0.
So, 99 is rounded-off to 100.
For 215, the Ones Place digit is 5 and Tens place digit is 1.
Since 5 is equal to 5, the digit in Ten’s place will be increased by 1 i.e., (1+1=2) and the digit in the One’s place is replaced with a 0.
So, 215 is rounded-off to 220.
For 1453, the Ones Place digit is 3 and Tens place digit is 5.
Since 3 is less than 5, the digit in Ten’s place will remain the same, and the digit in the One’s place is replaced with a 0.
So, 1453 is rounded-off to 1450.
For 2936, the Ones Place digit is 6 and Tens place digit is 3.
Since 6 is greater than 5, the digit in Ten’s place will be increased by 1 i.e., (3+1=4) and the digit in the One’s place is replaced with a 0.
So, 2936 is rounded-off to 2940.
So, the correct answer is 30, 30, 50, 40, 40, 50, 60, 60, 100, 220, 1450, 2940.
Hence, option 3 is correct.

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