N+10 means a number multiplied by 10
The answer is p(x) = 25x - 50
profit = total selling price- cost
x = number of bowls he must sell to make a profit
if he sell 1 bowl he will make a lost
2 bowls even up
thus he must sells 3 bowls or more to make a profit
D is the answer
(4+8)+1 = 13
4+(8+1) = 13
Therefore equation D is true