When the number of tens digit of double digits integer is subtracted from the number of ones digit, it becomes five.
As for the number that replaced the number of tens digit and ones digit, it becomes bigger by seven than the double of the original integer.
Find this integer.
Answer
38
Solution
This integer is assumed to be AB.
10 × B + A = (10 × A+ B) × 2 + 7
According to ① and ②, 11 × B = 95 - 7 = 88.
As for the number that replaced the number of tens digit and ones digit, it becomes bigger by seven than the double of the original integer.
Find this integer.
Answer
38
Solution
This integer is assumed to be AB.
B - A = 5---- ①
10 × B + A = (10 × A+ B) × 2 + 7
then it is to be 8 × B - 19 × A = 7-----②
① is multiplied by 19 to be 19 × B - 19 × A = 95.
According to ① and ②, 11 × B = 95 - 7 = 88.
Therefore, B = 88 / 11 = 8.
A = 8 - 5 = 3.
