Convert the following mixed numbers into improper fractions. Simplify your answers and express them in their lowest terms.

a. 15&5/6=

To convert a mixed number to an improper fraction, we need to multiply the whole number by the denominator of the fraction and add the numerator.

For 15&5/6:
Step 1: Multiply the whole number (15) by the denominator (6): 15 * 6 = 90
Step 2: Add the numerator (5) to the result from step 1: 90 + 5 = 95

So, 15&5/6 as an improper fraction in lowest terms is 95/6.