The right answer is 34.78%
The interphase is the period of the cell cycle that the cell transcribes its genes and the chromosomes are duplicated. It can be subdivided into several phases:
* phase G1
* phase S: during which the chromosomal material is doubled by DNA replication. This is called chromosome duplication.
* phase G2.
Phase G1 is the longest phase of the interphase (its duration depends on the type of cell), followed by phase S, then phase G2.
To calculate the proportion of phase S in the interphase simply make the division:
phase duration S / interphase duration = 8/23 = 0.3478 (in percentage that is 34.78% (0.3478*100)).
