4. The average of three numbers is 12. If two of the numbers is 13 and 15.
then which is the third number?
years
(B) & (C) 16 (D) 20
(A) 6
Answers
Step-by-step explanation:
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\textsf{\underline{\underline{Given :}}}
Given :
Average of the numbers = 12
The given 2 Numbers = 13 and 15
Total Observations = 3
\textsf{\underline{\underline{To find : }}}
To find :
The third number
\textsf{\underline{\underline{Solution :}}}
Solution :
Consider the number as x
Average/Mean =
\tt{\implies \dfrac{sum \: of \: \: observations}{total \: observations} }⟹
totalobservations
sumofobservations
\tt{\implies \dfrac{x + 13 + 15}{3} = 12 }⟹
3
x+13+15
=12
\tt{\implies \dfrac{x + 28}{3} = 12 }⟹
3
x+28
=12
\tt{\implies \: x + 28 = 12 \times 3}⟹x+28=12×3
\tt{\implies \: x + 28 = 36}⟹x+28=36
\tt{\implies \: x = 36 - 28}⟹x=36−28
\tt{\implies \: x = 8}⟹x=8
\large{\boxed{\bigstar{\sf \: {x = 8 }}}}
★x=8
\therefore∴ \text{The Third number is 8}The Third number is 8
\textbf{\underline{\underline{Verification :-}}}
Verification :-
\tt{\implies \dfrac{x + 13 + 15}{3} = 12 }⟹
3
x+13+15
=12
\tt{\implies \dfrac{8 + 13 + 15}{3} = 12 }⟹
3
8+13+15
=12
\tt{\implies \dfrac{36}{3} = 12 }⟹
3
36
=12
\tt{\implies 12 = 12 }⟹12=12
{\boxed{\bigstar{\sf \: { LHS = RHS }}}}
★LHS=RHS
\therefore∴ \text{The Third number is 8}The Third number is 8
Answer:
8
Step-by-step explanation:
since there are three no. than average=12*3 i.e. 36.
so, 15 + 13 - 36= 8