A tsunami generates two types of waves: a primary wave that travels at 200 m/s and a secondary wave that travels at 100 m/s. If a warning system detects these waves arriving 15 minutes apart, calculate the distance from the tsunami's origin to the detection point.

• A. $1.5 \times 10^{5} \mathrm{~m}$
• B. $1.8 \times 10^{5} \mathrm{~m}$
• C. $2.0 \times 10^{5} \mathrm{~m}$
• D. $2.5 \times 10^{5} \mathrm{~m}$

Answer: (B)