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4.Average

easy

The average age of $5$ sisters is $20 \,year.$ If the age of the youngest sister be $4 \,year,$ what was the average age of the group of sisters at the birth of the youngest sister in $year$ ?

A

$25$

B

$15$

C

$18$

D

$20$

Solution

Total age of $5$ sisters $=100$ years.

Total age of a group of sister at the birth of youngest sister $=100$ $-4 \times 5=80$ years.

Average age of group of sisters $\frac{80}{4}=20$ years

Std 13

Quantitative Aptitude

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