Question

The average age of three brothers is 15 years.If the age of two brothers is 15yrs and 12 years,find the age of the third brother. Please give answer

Answer 1

Mean age = 15 years

No. of items = n

a = 15 yrs

b = 12 yrs

c = ?

Average = (a + b + c)/3

15 = 15 + 12 + c / 3

45 = 27 + c

c = 18 yrs

Answer 2

$\mathfrak{Answer:}$

= 18 years.

$\mathfrak{Step-by-Step\;Explanation:}$

$\underline{\bold{Given\;in\;the\;Question:}}$

• The age of two brother is 15 years and 12 years.
• Average of all three brother = 15 years.

$\mathbb{SOLUTION:}$

Let the age of third brother be x years.

$\bigstar\quad\textbf{We know that : \boxed{\bold{Average=\dfrac{Sum\;of\;observations}{No.\;of\;observations}}}}\\\\\\\mathfrak{According\;to\;Question:}\\\\\\\implies\tt{\dfrac{15+12+x}{3}=15}\\\\\\\implies\tt{27+x=45}\\\\\\\implies\tt{x=45-27}\\\\\\\implies\tt{x=18.}\\\\\\\\\boxed{\boxed{\bold{The\;age\;of\;third\;brother=18\;years.}}}$