Sat 数学历年真题

ii

We have 3 variables here, so this usually means a two-stepper. Let’s use our variables and givens to translate the “math speak” into equations.

Train B’s speed.

A B

A=3B Equation 1

C A C=2A Equation 2

Now we’ve got two equations, so let’s use ‘em. What are we looking for again? C’s speed, that’s right. B=7 (Given) A=3B

A=3(7) = 21 C=2A

C=2(21) = 42 E is the correct answer. Test 1 Section 3 Question 3 Average Problem

Know that “average” and “mean” are the same. Average = Sum of the terms / # of terms.

Let’s write our givens:

Terms: x, 5x, 6x

Number of Terms: 3 Average of terms: 8