Question

If Ken spends 1/5 of his money on a dictionary, he gives $21 to his brother, and has 1/2 of his money left, how much money does Ken have left?

Answer 1

let ken have money=x
he spend 1/5 money for dictionary=x/5 $
he gave money to his brother = 21 $
left money = x/2
total money he had
x=x/5+21+x/2
solve the equation
multiply both side by 10,we get
10x=2x+210+5x
3x=210
x=70

total money ken have =70 $ 

Answer 2

Let Ken have x $
He spent x/5 on dictionary
He gave 21$ to his brother
Money left with him is x/2 $
ATQ we have x/5 + 21+x/2=x
                   ⇒  2x+210+5x=10x
                   ⇒ 3x=210 or x=70
Kent is left with 70/2= 35$