Question

Assertion: 100 years make 10 decades
Reason: 1 decade = 10 years
(A) Both assertion and reason are correct and reason is the correct explanation of assertion.
(B) Both assertion and reason are correct but reason is not the correct explanation of assertion.
(C) Assertion is correct but reason is incorrect.
(D) Assertion is incorrect but reason is correct.

Answer 1

The word ‘decade’ is derived from ancient Roman and Latin words which mean ten, just like a decagon has ten sides, decathlon has ten events, dekameter has ten meters and decahedron has ten faces. This question requires application of the unitary method.

Complete Step by Step Solution
A decade is a period of 10 years. The word is derived (via French and Latin) from dekas, which means a group of ten. This is just like a decade of the Rosary has 10 beads. It comes from the Latin ‘decem’ for ten. In the Roman legions a decade was their ‘squad’.
Decades may describe any ten-year period, such as those of a person's life, or refer to specific groupings of calendar years.
Thus, the statement stated under reason, ‘1 decade = 10 years’ stands true.
For 1 decade, we have 10 years.
Here, we apply the unitary method.
For 10 decades, we shall have $10 \times 10 = 100$ years. This relation comes from the reason statement.
Thus, the assertion is also correct and is proved from the reason statement. Both assertion and reason are correct and reason is the correct explanation of assertion.
The correct answer is Option A.

Note
Chronology is the science of arranging events in their order of occurrence in time. Consider, for example, the use of a timeline or sequence of events. It is also "the determination of the actual temporal sequence of past events".
1 biennium is equal to 2 years, 1 lustrum is equal to 5 years, 1 decade is equal to 10 years, 1century(10 decades) is equal to 100 years and 1 millennium is equal to 1000 years.