What percentage of values between 1 and 70 contain 1 or 9 as the unit digit?
A. 1
B. 14
C. 20
D. 21
Answer:C
What percentage of values between 1 and 70 contain 1 or 9 as the unit digit?
A. 1 B. 14 C. 20 D. 21
Explanation: Clearly, numbers with 1 or 9 in the unit's digit have squares with 1 as the last digit. 1, 9, 11, 19, 21, 29, 31, 39, 41, 49, 51, 59, 61, and 69 are examples of such numbers from 1 to 70.The number of such numbers equals 14.The required proportion is 14 x 100/70 percent, which equals 20%.