1) What number should be subtracted from 3, 5, 6, 7 so that the resulting numbers in this order form a proportion? A) 8 B) 7 C) 9 D) 5 E) 6 Answer: Option CExplanation:Let the number $x$ be subtracted from each given number $\frac{3-x}{5-x}=\frac{6-x}{7-x}$ $\Rightarrow (3-x)(7-x)=(6-x)(5-x)$ $x^{2}-10x+21$ $=x^{2}-11x+30$ $\Rightarrow x=30-21$ $=9$
