Q7 of 80 Page 56

After 15 years, Mary’s age will be four times of her present age. Find her present age.

Let Mary’s present age be x years.

Her age after 15 years = (x + 15) years.


According to the given condition,


4x = x + 15


⇒ 4x – x = 15 (Transposing x to LHS)


3x = 15


⇒ x = (Transposing 3 to RHS)


x = 5


∴ Mary’s present age is 5 years.


More from this chapter

All 80 →
5

Find three consecutive numbers such that if they are divided by 10, 17, and 26 respectively, the sum of their quotients will be 10.

(Hint: Let the consecutive numbers = x, x + 1, x + 2, then)

 6

In class of 40 pupils the number of girls is three-fifths of the number of boys. Find the number of boys in the class.

 8

Aravind has a kiddy bank. It is full of one-rupee and fifty paise coins. It contains 3 times as many fifty paise coins as one rupee coins. The total amount of the money in the bank is` 35. How many coins of each kind are there in the bank?

 9

A and B together can finish a piece of work in 12 days. If ‘A’ alone can finish the same work in 20 days, in how many days B alone can finish it?