Answer:
To answer the problem above we let x be the number of people who prefers salad and y be the number of people who chose steak. For lunch they will be spending $41. That is,
7x + 10y = 41
Now, for dinner they will be spending $51. That is,
9x + 12y = 51
The values of x and y from both equations are 3 and 2, respectively. Therefore, 3 people will choose a salad