Question

What percentage of numbers from 1 to 90 has 1 or 8 in the unit's digit?
(A) 10%
(B) 20%
(C) 25%
(D) 45%​

Answer 1

Answer:

(B) 20%

Step-by-step explanation:

Answer 2

Answer:

Step-by-step explanation:

Percentage of numbers from 1 to 90 that has 1 or 8 in the unit's digit is $20$%.

Percentage:

• A number or ratio expressed as a fraction of 100 is called a percentage.
• It is frequently indicated by the percent sign, "%" .

$Percentage =\frac{value}{Total Value} *100$

Given:

Numbers 1 to 90.

To Find:

We need to find the percentage of numbers from 1 to 90 has 1 or 8 in the unit's digit.

Solution:

Number that has 1 as unit digit from 1 to 90,

• $1,11,21,31,41,51,61,71,81$

• $9$ numbers that have $1$ has unit digit.

Number that has 8 as unit digit from 1 to 90,

• $8,18,28,38,48,58,68,78,88$

• $9$ numbers that have $8$ has unit digit.

Number of unit digits of 1 or 8 $=9+9=18$

Out of 90 numbers, $18$ numbers have unit digits.

Now,

$Percentage =\frac{value}{Total Value} *100$

$Percentage =\frac{18}{90} *100$

$Percentage= 0.2*100$

$Percentage= 20$

Therefore, percentage of numbers from 1 to 90 that has 1 or 8 in the unit's digit is $20$%.

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