If s/t = 2, then the value of which of the following can be determined?

BTGModeratorVI wrote: ↑

Wed Feb 26, 2020 4:09 pm

If s/t = 2, then the value of which of the following can be determined?

I. 2t/s
II. (s - t)/t
III. (s - 1)/(t - 1)

A. I only
B. III only
C. I and II only
D. II and III only
E. I, II, and III

Answer: C
Source: Official Guide

So, we know that s/t = 2; thus, s = 2t

Let's analyze each statement by plugging-in the value of s = 2t.

I. 2t/s: 2t/2t = 1. The value can be determined.

II. (s – t)/t: (2t – t)/t = t/t = 1. The value can be determined.

III. (s – 1)/(t – 1): (2t – 1)/(t – 1). The value cannot be determined.

The correct answer: C

Hope this helps!

-Jay
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BTGModeratorVI wrote: ↑

Wed Feb 26, 2020 4:09 pm

If s/t = 2, then the value of which of the following can be determined?

I. 2t/s
II. (s - t)/t
III. (s - 1)/(t - 1)

A. I only
B. III only
C. I and II only
D. II and III only
E. I, II, and III

Answer: C
Source: Official Guide

I. 2t/s
If s/t = 2, then t/s = 1/2
So, 2t/s = 2(t/s) = (2)(1/2) = 1
So we CAN determine the value of 2t/s


II. (s - t)/t
Here, we can use a nice fraction property that says: (a - b)/c = a/c - b/c
We get: (s - t)/t = s/t - t/t = s/t - 1 = 2 - 1 = 1
So we CAN determine the value of (s - t)/t


III. (s - 1)/(t - 1)
Notice that, if s/t = 2, it COULD be the case that s = 2 and t = 1
When we plug these values into the expression we get: (s - 1)/(t - 1) = (2 - 1)/(1 - 1) = 1/0, which is undefined.
So we CANNOT determine the value of (s - 1)/(t - 1)

Answer: C

Cheers,
Brent

BTGModeratorVI wrote: ↑

Wed Feb 26, 2020 4:09 pm

If s/t = 2, then the value of which of the following can be determined?

I. 2t/s
II. (s - t)/t
III. (s - 1)/(t - 1)

A. I only
B. III only
C. I and II only
D. II and III only
E. I, II, and III

Answer: C
Source: Official Guide

Since s = 2t, we can substitute 2t for s in each expression:

I. 2t / 2t = 1

I is correct.

II. (2t - t) / t = 1

II is correct.

III. (2t -1) / (t - 1)

We see that different values of t will yield a different value of the expression, so III is not correct.

Answer: C