Give the number a name. Let's call it ' P '.
One third of the number is P/3
The sum of one third the number and 25 is P/3 + 25
Twice the number is 2P .
The sum is as much as twice the number P/3 + 25 = 2P
What's so tough about that ? ! ?
Would you like to know what the number is ?
P/3 + 25 = 2P
Subtract P/3 from each side: 25 = 5/3 P
Multiply each side by 3 : 75 = 5 P
Divide each side by 5 : 15 = P