Answer:
20 years
Step-by-step explanation:
A decade is a period of 10 years. The word is derived (via French and Latin) from the Ancient Greek: δεκάς, romanized: dekas, which means a group of ten. Decades may describe any ten-year period, such as those of a person's life, or refer to specific groupings of calendar years.
2 × 10 = 20
