Joc sold 20 more than half his toys in January. He sold 15 more than half remaining number of toys in February. He had 75 toys left March before. How many toys did Joc carry at first?
+130511 Let N be the number he started with
In Jan....he sold N/2 + 20
So....after this.....he had N - (N/2+20) = N/2 - 20 left
If Feb he sold (1/2) (N / 2 - 20) + 15
So
What he started with - those sold in Jan - those sold in Feb = 75
So we have
N - ( N/2 + 20) - [ (1/2) (N/2 - 20) + 15 ] = 75 simplify
N/2 - 20 - (1/4)N + 10 - 15 = 75
(1/4)N - 25 = 75
(1/4) N = 75 + 25
(1/4)N = 100 multiply through by 4
N = 400
Proof
He starts with 400
He sells (1/2)400 + 20 = 220
He has 400 - 220 = 180 left
He then sells (1/2)(180) + 15 = 105
He has 180 - 105 = 75 left
