Average of X_{1}, X_{2} and X_{3} is 14 . Twice sum of X_{2} and X_{3} is 30 . value of X_{1} ?

English

Gujarati

Hindi

4.Average

medium

The average of $X_{1}, X_{2}$ and $X_{3}$ is $14 .$ Twice the sum of $X_{2}$ and $X_{3}$ is $30 .$ What is the value of $X_{1} ?$

A

$20$

B

$27$

C

$16$

D

$12$

Solution

Given average of $X_{1}, X_{2}$ and $X_{3}=14$

$i.e.$ $X_{1}+X_{2}+X_{3}=14 \times 3=42$ ……$(1)$

$2\left(X_{2}+X_{3}\right)=30$

$X_{2}+X_{3}=15$…..$(2)$

$(1)-(2) \Rightarrow X_{1}=42-15=27$

Standard 13

Quantitative Aptitude

Share

Similar Questions

The average weight of a group of $20$ boys was calculated to be $89.4 kg$ and it was later discovered that one weight was misread as $78 kg$ instead of the correct one of $87 kg$. The correct average weight is in $kg$

medium

Out of seven given numbers, the average of the first four numbers is $4$ and that of the last four numbers is also $4 .$ If the average of all the seven numbers is $3,$ then fourth number is?

easy

The mean of $100$ items was $46 .$ Later on it was discovered that an item $16$ was misread as $61$ and another item $43$ was misread as $34 .$ It was also found that the number of items twas $90$ and not $100 .$ Then what is the correct mean?

medium

Three years ago, the average age of a family of $5$ members was $17\, years.$ A baby having been born, the average age of the family is the same today. The present age of the baby is (in $years$)

hard

The average of runs of a cricket player of $10$ innings was $32 .$ How many runs must he score in his next innings so as to increase his average of runs by $4 ?$

medium