Number multiplication puzzle

John thought of a number. He multiplied it by four and added 18 to the result, getting ten times the number 8. What number did John think of?

Final Answer:

x =  15.5

Step-by-step explanation:


4x + 18 = 10·8

4·x + 18 = 10·8

4x = 62


x = 62/4 = 15.5

x = 31/2 = 15.5

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