Answer: b. 3.88
Reasoning: It appears that the space between each number is divided into 5 spaces, and beause decimal places are divided into tenths, simply divide ten by the fove spaces, and each dash will represent an increase in two hundredths (x.x0) in the decimal. For Q, it is located on the third dash from 3.8, therefore we have to multiply the three ticks by two hundredths for each tick, and that will come out to 6 hundredths, and when added to that 3.8, we can determine that Q is located at 3.86. The same can also go for R, as it is located one tick from 3.9, and one tick times 2 added hundredths will equal adding two more hundredths to 3.9, allowing us to determine that R is located at 3.92. So, with Q at 3.86 and R at 3.92, our answer is between those two numbers, the only option being our answer of 3.88 (b).