Average marks of a student obtained in Physics, Chemistry and Biology is 70. If student obtained 90,

English

Gujarati

Hindi

4.Average

medium

The average marks of a student obtained in Physics, Chemistry and Biology is $70.$ If the student obtained $90\, marks$ in Mathematics, then the new average is

A

$80$

B

$78$

C

$76$

D

$75$

Solution

Average age of $18$ persons $=32$ years $6$ months

Age of persons left $=65$ years $\times 2+50$ years $\times 1$

$\therefore$ The sum of ages of persons remaining

$=18 \times 32$ years 6 months $-2 \times 65-1 \times 50$

$=585-130-50=405$

$\therefore$ Average age of remaining persons $=\frac{405}{15}=27$ years

Standard 13

Quantitative Aptitude

Share

Similar Questions

The average age of $8$ men is increased by $2\, years.$ When $2$ of them, whose ages are $20\, years$ and $24 \,years$ respectively, are replaced by $2$ women. What is the average age of these two women ? (in $years$)

medium

The average of $10$ mumbers is $7 .$ What will be the new average if each of the numbers is multiplied by $8 \,?$

medium

The average age of a graph of $9$ students is $20\, years.$ When $6$ more students joined the group, the average age falls by $2\, years.$ Then the average age of new students is

medium

The average of first $25$ numbers is $10$ and the average of the next $25$ numbers is $12 .$ The average of all $50$ numbers is

easy

The average of three consecutive odd numbers is $12$ more than one-third of the first of these numbers. What is the last of the three numbers ?

medium