Answer:
15
Step-by-step explanation:
Fast and loose: To go from 8 to 12 minutes you're adding half the time (4 minutes). So it has time to burrow only half the holes in the extra time, so 5. Total, 10+5=15.
Crunching numbers: it's a simple proportion:[tex]10:8 = x :12[/tex] from which, cross-multiplying you get [tex]8x=12\times10 \rightarrow 8x=120 \rightarrow x=15[/tex]
