Question

14. Four sisters are 30 months apart in age. If the sum of their ages is 31 years, how old is the
youngest sister
(a)10 years
(b) 6 years
(c)4 years
(d) 2 years
​

Answer 1

Answer:

The youngest sister will be 10 years old

Answer 2

Answer:

(c)4 years

Step-by-step explanation:

Let x be the age of the youngest sister ( in months ),

∵ sisters are 30 months apart in age.

So, the age of other three sisters,

x + 30, x + 60, x + 90,

Thus, the sum of their ages( in month ) = x+x+30+x+60+x+90

= 4x + 180

Now, 1 year = 12 months,

That is, the sum of their ages ( in year ) =  $\frac{4x+180}{12}$

According to the question,

$\frac{4x+180}{12}=31$

4x + 180 = 372

4x = 192

x = 48

Hence, the age of younger sister = 48 months = 4 years.

OPTION C is correct.