Gujarati
Hindi
4.Average
hard

Out of four numbers the average of the first three is $16$ and that of the last three is $15 .$ If the last number is $20$ then the first number is

A

$21$

B

$23$

C

$28$

D

$25$

Solution

Let the $4$ numbers be $a, b, c, d$.

Average of $a, b, c=16$

$a+b+c=48$

Average of $b, c, d=15$

$b+c+d=45$

$(a+b+c)-(b+c+d)=48-45$

$a-d=3$

$a-20=3$

$a=23$

Standard 13
Quantitative Aptitude

Similar Questions

Start a Free Trial Now

Confusing about what to choose? Our team will schedule a demo shortly.