Of three numbers, average of first and second is greater than average of second and third by 15 . di

English

Gujarati

Hindi

4.Average

medium

Of the three numbers, the average of the first and the second is greater than the average of the second and the third by $15 .$ What is the difference between the first and the third of the three numbers?

A

$15$

B

$45$

C

$60$

D

$30$

Solution

Let $x, y$ and $z$ be the numbers.

$\frac{x+y}{2}=\frac{y+z}{2}+15$

$\frac{x-z}{2}=15$

$x-z=2 \times 15=30$

Standard 13

Quantitative Aptitude

Share

Similar Questions

The arithmetie mean of the scores of a group of students in a test was $52 .$ The brightest $20 \%$ of them secured a mean score of $80$ and the dullest $25 \%$ a mean score of $31.$ The mean score of remaining $55 \%$ is

medium

The average weight of $A, B$ and $C$ is $84 \,kgs.$ If $D$ joins, the average weight now is $80 \,kgs$. If another person $E$ who is $3\, kgs$ heavier than $D$ replaces $A$ then the average weight of $B, C, D$ and $E$ becomes $79\, kgs.$ what is the weight of $A $ in $kg$ ?

medium

$16$ children are to be divided into two groups $A$ and $B$ of $10$ and $6$ children. The average percent marks obtained by the children of group $A$ is $75$ and the average per cent marks of all the $16$ children is $76 .$ What is the average per cent marks of children of group $B$ ?

medium

The average score of Rahul, Manish and Suresh is $63.$ Rahul's score is $15$ less than Ajay and $10$ more than Manish. If Ajay scored $30$ marks more than the average score of Rahul, Manish and Suresh, what is the sum of Manish's and Suresh's scores ?

easy

Of the three numbers, second is twice the first and is also thrice the third. If the average of the three numbers is $44,$ the largest number is

medium