Answer: 3 people ordered soup.
Explanation:
Let x be the number of people ordered salad and y be the number of people ordered soup.
As per given,
x=2y (i)
7.50x+6.25y= 63.75 (ii)
Substitute value of c =2y in (ii) , we get
7.50(2y)+6.25y= 63.75
⇒ 15y+6.25y = 63.75
⇒21.25y = 63.75
⇒ y= 3 [divide both sides by 21.25]
Then, x= 2(3) =6
So 6 people ordered salad and 3 people ordered soup.