d = 30 + 2(40 – s) The machine begins the day with $30 inside, so that’s the “30 +” part. Easy enough. The variable s is defined as how many sodas the machine has in it, but what we really care about is how many sodas are sold. We know the machine begins the day with (more…)

You can make two equations here. First, you know the total number of marbles is 103, so: The second equation is more complicated, so let’s do it in parts. First, he gives away 15 red marbles, so he should have r – 15 left. He gives away 2/5 of his blue marbles, so he should have (more…)

This question comes from my own book, so my tips on how to deal with these can be found in the same chapter. The main key to getting it right is making sure you translate the words into math correctly. Note that although the question tells you that Tariq makes brownies and Penelope makes cookies, (more…)

Pilar is a salesperson at car company. Each car costs at least $15,000. For each car she sells, she gets 6% commission of the amount by which selling price exceeds $10,000. If Pilar sells a car at d dollars, which function gives her the commission in dollars on sale?

A) C(d)=0.06(d-10000)

B) C(d)=0.06(d-15000)

C) C(d)=0.06(10000-d)

One way to make sure you get questions like these right is to plug in some values to see which equation makes sense. For example, you might choose to plug in 0 for h here because you know that at zero feet above sea level the boiling point should be 212° F. Choices C and D (more…)

Hello! Could you please explain how to answer Question #16 from Section #3 from official practice SAT test #5? Thank you in advance!

This no-calculator prompt is from the Daily Practice app:

Lisa gives her little brother Sam a 15-second (sec) head start in a 300-meter (m) race. During the race, Sam runs at an average speed of 5 m/sec and Lisa runs at an average speed of 8 m/sec, not including the head start.

Which of the following best approximates the number of seconds that had passed when Lisa caught up to Sam?

A. 5

B. 25

C. 40

D. 55

Test 8 Section 3 #13

Test 4 Section 3 #20 please. Also Mike, I still didn’t know how to answer the question even after I went and reviewed it from the official test breakdown section of your book.

Test 7 Section 3 #14

Test 3 Section 4 #30

Test 3 Section 4 #24

Can you help with 33 in test 7 section 4?

Can you do test 4 section 4 number 35 please?

Could you solve Test 6, Section 4, number 18 for me? Thanks!