A number is larger than half of 100. It is more than 6 tens and less than 8 tens. The sum of its digits is 9. The tens digit is the double of the one's digit. What is the number?
A number is larger than half of 100. It is more than 6 tens and less than 8 tens. The sum of its digits is 9. The tens digit is the double of the one's digit. What is the number? Correct Answer 63
Concept used:
A two-digit number is formed by the combination of the unit place and the tens place
Calculation:
Let the unit and the tens digit be x and y
Number = 10y + x
Now, A/Q
The tens digit is double of the one's digit
y = 2x ----(1)
The sum of its digit is 9
x + y = 9 ----(2)
From the eq (1) and eq (2)
x + 2x = 9
⇒ 3x = 9
⇒ x = 3
From eq (1), y = 2 × 3 = 6
Number = 10y + x = 10 × 6 + 3 = 63
The number is greater than half of 100 i.e 50 and more than 6 tens i.e 60 and less than 8 tens i.e 80
∴ The required number is 63
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Feb 20, 2025