Question

What percentage of numbers from 1 to 70 have 1 or 9 in the unit's digit?
A1
B. 14
C. 20
D. 21​

Answer 1

Question

What percentage of numbers from 1 to 70 have 1 or 9 in the unit's digit?

A. 1

B. 14

C. 20

D. 21​

Step-by-step explanation:

• We have to find the percentage of numbers that have 1 or 9 in the unit's place.

• From 1 to 70 we have 2 × 7 numbers that have 1 or 9 in the unit's place.

The numbers are as follows:

• 1, 9
• 11, 19
• 21, 29
• 31, 39
• 41, 49
• 51, 59
• 61, 69

• So the total numbers that have 1 or 9 in the unit's place are 14.

• And total numbers are 70.

• Now, the percentage of numbers that have 1 or 9 in the unit's place is

• $\frac{14}{70} \times 100$ %

• $\frac{1}{5} \times 100$ %

• 20%

Hence, the percentage of numbers from 1 to 70 have 1 or 9 in the unit's digit is 20%.

So, the correct option is C. 20.