A man goes by motor boat a certain distance upstream at 15 km/hr and return the same downstream at 20 kin/hr. The total time taken for the journey was 7 hrs. Find how far did he go.

A) 60 km

B) 50 km

C) 40 km

D) 120 km

Correct answer:
A) 60 km

Description for Correct answer:
\( \Large \frac{d}{20}+\frac{d}{15}=7 \)

Therefore, d = 60 km


Please provide the error details in above question