When you reverse the digits of the number 13 the number increases by 18 how many other two digit numbers increase by 18 when their digits are reversed choose one 7 5?

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Calculation:

Let the unit digit be x and tens digit be y

According to the question,

⇒ 10y + x - (10x + y) = 18

⇒ 9y - 9x = 18

⇒ y - x = 2

It means that difference of digits of two-digit numbers is 2.

∴ Six cases other than (13, 31) are possible

(24, 42) (35, 53) (46, 64) (57, 75) (68, 86) (79, 97)

Mistake Points

Here we cannot take (20, 2)

Because 2 is not a two-digit number. Normally we do not write numbers from 1 - 9  as 01, 02, 03, 04, 05, 06, 07, 08, and 09.

When you reverse the digits of the number 13, the number increases by 18. How many other two-digit numbers increase by 18 when their digits are reversed?

Answer

Let the two-digit number be ab.

When the digits are reveres (ba), the number is increased by 18.

(10a+b) - (10b+a) = 18

a - b = 2

All such numbers that have unit's digit greater than ten's digit by 2.

Numbers are (except 13) 24, 35, 46, 57, 68, 79. So. there are 6 other numbers.

The correct option is B.

When you reverse the digits of the number 13 , the number increases by 18. How many other two digit numbers increase by 18 when their digits are reversed?

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