Mean = Sum of Numbers/Total number of numbers(items) When you count the numbers, 5,2x,4 and 3 , you will get 4 , hence total number of numbers =4 Mean =5 Sum means add all the numbers ⇒5=(5+2x+4+3)∕4 Solve for x Get rid of the fraction by multiplying both sides of the equation by the LCM of the denominators (1 and 4). The LCM of the denominators is 4 hence multiply both sides by 4 5=5∕1 ⇒5×4=5+2x+4+3 20=5+2x+4+3 20=5+4+3+2x 20=12+2x 20−12=2x 8=2x Divide both sides by 2 8∕2=2x∕2 4=x ⇒x=4