An integer is defined to be upright if the sum of its first two digits equals its third digit. For example, 145 is an upright integer since 1+4=5. How many positive 3- digit integers are upright?
Answer Choices
A. 28
B. 39
C. 36
D. 45
E. 50
An integer is defined to be upright if the sum of its first two digits equals its third digit. For example, 145 is an upright integer since 1+4=5. How many positive 3- digit integers are upright?
Answer Choices
A. 28
B. 39
C. 36
D. 45
E. 50