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The units digit is 5 and therefore the tens digit is 5 + 3 which is 8. The number is 85.

Example 2: Arjun is twice as old as Shriya. Five years ago his age was three times
Shriya’s age. Find their present ages.

Solution: Let us take Shriya’s present age to be x years.

ThenArjun’s present age would be 2x years.
Shriya’s age five years ago was (x – 5) years.

Arjun’s age five years ago was (2x – 5) years.

It is given that Arjun’s age fiveyearsago was threetimesShriya’s age.
Thus, 2x – 5 = 3(x – 5)

or 2x – 5 = 3x – 15

or 15 – 5 = 3x – 2x
or 10 = x

So, Shriya’s present age = x = 10 years.

Therefore, Arjun’s present age = 2x = 2 × 10 = 20 years.

Example 3: The number of boys and girls in a class are in the ratio 5:4. If the number of
boys is 9 more than the number of girls, then number of boys is 9.

Solution: Let us take the common factor be x

Then the no. of boys be 5x and no. of girls be 4x
The no. of boys is 9 more than the no. of girls.

No. of boys -No. of girls = 9

5x – 4x = 9
X= 9

Therefore the no. of boys is 5x = 5*9 = 45 and the no. of girls is 4*9 = 36.

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