Question

The average of 4no.s is 60 if one of them is less than the average of the remaining by 12 the number

Answer 1

Let Number=X1+X2+X3+X4

AVERAGe Of 4 number=60
Then
$\frac{x1 + x2 + x3 + x4}{4} = 60$
If one of the number is less by AVERAGe of Remaining 3 number =12
Let x1 is less

Then Now
$\frac{x2 + x3 + x4 } {3} = 60 -12\\ = \frac{x2 + x3 + x4}{3} = 60 -12 \\ \frac{x2 + x3 + x4}{3} = 48 \\ x2 + x3 + x4 = 48 \times 3 = 144$
Now Sum of x2+x3+x4=144
Now Insert it on formula
$\frac{x1 + 144}{4} = 60 \\ = x1 + 144= 60 \times 4 = 240 \\ x1 = 240 - 144 \\ x1 = 96$
Number=96