Question

A number, half of that number, and 1/5 of that number added. Result is 51. What is the original number?

Answer 1

30

Explanation:

let the original number be x then

x +
`(1)/(2)` x +
`(1)/(5)` x = 51

multiply through by the lowest common multiple of 2 and 5, that is 10, to eliminate the fractions

10x + 5x + 2x = 510

17x = 510 ( divide both sides by 17 )

x = 30

Thus the original number is 30