Question

Average of 20,30,40, x is 40.find the value of x

Answer 1

very simple average 20+30+40+x/4=40

90+x=160

x=160-90

x=70

Answer 2

the trick to know that if we have got our answer correct

...retrace the path back again and keep the value of X in the equation and see that if the average of that is equal to 40...... I hope this answer helps you