Which of the following pairs of class limits would be appropriate for grouping the numbers 12, 15, 10, and 17 ?
a. 9-13 and 13-17
b. 10-12 and 15-17
c. 10-12 and 13-17
d. 10-13 and 14-17

d. 10 -13 and 14 -17

Because:

1) the range of the values is 10 to 17 (inlcude 8 numbers), which divided by 2 is 4, and the range of the selected classes is 4, so you can have two class interval of the same size, which is what the option d represents..

2) all the values are included (some pair of intervals excluded some numbers)

First step is to get rid of the square root. remember that a square root is the same as raising to the (1/2) power. see below: multiply exponents per exponent rules to get: remember you subtract exponents from the denominator and add exponents in the numerator so: simplify further: so a is the correct choice. if you don't understand this google exponent rules and it will you understand. look at the image results.