Question
A number consists of two digits. The sum of the digits
is 7. If 9 is subtracted from the number, its digits are interchanged. Find the number.Solution
Let the ten’s digit be x. Then, unit digit = 7- x . No.= 10x + (7-x ) = 9x + 7 No. obtained by reversing the digits = 10(7- x ) + x = 70-9x (9x + 7) - 9 = 70- 9x , or, 9x + 9x = 70 - 7 + 9, or, 18x = 72 or x = 4, so ten’s digit = 4 and unit digit = 3 Hence, the required number = 43.
- Find the wrong number in the given number series.
4, 10, 22, 46, 92, 186 Find the wrong number in the given number series.
26, 38, 60, 110, 206, 398
Find the wrong number in the given number series.
25, 38, 53, 74, 97, 126
11, 1341, 3070, 5267, 8011, 11386
Find the wrong number in the given number series.
41, 42.7, 46.1, 51.2, 58, 64.7Find the wrong number in the given number series.
12, 24, 72, 216, 1440, 8640
The following numbers follow a certain pattern. Identify the odd one out.
9, 25, 65, 191, 569, 1703
63, 124, 215, 345, 511, 728
1460, 1443, 1430, 1415, 1404, 1395
112, 236, 374, 546, 790, 1376
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