When 42 is divided into two parts and 5 times of the first part is added to 10 times of the second part, it is 360. Find the first part.
Let the first part = x , therefore, second part is 42 – x 5 x + (42 – x ) 10= 360, or 5x + 420 – 10x = 360, or x = 12 First part = 12
