Question

four sisters are 30 months apart in age is sum of their ages is 31 years how many how old is the younger sister​

Answer 1

Answer:

Let the age of younger sister be X years.

Then the ages of remaining elder sisters will be (X+2.5),(X+5) and (X+7.5) respectively.

Given that,

X+X+2.5+X+5+X+7.5= 31 years

Or,4x+15= 31 years

Or,4x= 16 years

Therefore, X= 16/4= 4 years.

Hence age of younger sister(X) is 4 years.

Answer 2

Let their ages be x, x+30, x+60, x+90
Sum= 31 years= 372 months
According to the question,
X+30+x+60+x+90+x= 372
4x+180= 372
4x= 192
x= 192/4
x= 48
So, age of youngest sister=48 months= 48/12 years= 4 years