## If y varies directly with the square of x…

If y varies directly with the square of x and y = 4.3 when x = 5, what is the value of y when x = 6?

A) 0.2
B) 3.0
C) 5.2
D) 6.2
E) 209.3

## Test 3 Section 4 #26

Test 3 Section 4 #26

## The table above lists the results of a survey of a random sample of 250 high school seniors and freshmen.

The table above lists the results of a survey of a random sample of 250 high school seniors and freshmen. Each student selected one subject that was his or her favorite.If the sample is representative of a high school with 2,000 freshmen and seniors, then based on the table, what is the predicted number of freshmen at the high school who would select math as their favorite high school subject? A) 520 B) 240 C) 65 D) 30

## The volume of water in a small pool is directly proportional to the depth of water…

The volume of water in a small pool is directly proportional to the depth of water. When there are 10 cubic feet of water in the pool, the depth of the water is 5 inches. How many cubic feet of water are in the pool when the depth of the water is 2 feet?

## Weekend Challenge – By request

Someone requested recently at my Q&A page that I post a challenge question about direct and inverse variation. I quickly agreed, but it’s taken me longer than I wanted it to because I’ve been having a hard time hitting the right level of difficulty for a challenge question. I’m still not sure I’ve nailed it, (more…)

## Weekend Challenge – Black Friday

Source: Nature’s Graffiti. Do you guys do the Black Friday thing? One time, about 7 years ago, I got up at 3 in the morning and met some friends to wait outside Best Buy. It was complete pandemonium, and I was not fast or ruthless enough to get the TV I wanted. Then, I got (more…)

## Direct and Inverse Proportionality (Variation)

There are two kinds of proportionality (some call these problems “variation” problems, but I’m sticking with proportionality) problems that you might see on the SAT: direct and inverse. I’m going to cover both here since I’m in the business of preparing you for any eventuality, but you should know that the the former is much (more…)