i got a question for physics paper 1

[igs_beast]

in this paper the first question please help http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Physics (0625)/0625_s11_qp_12.pdf
i got it a 132 and in the answers its written 66 so how is it possible

 

[crab cake]

the equation for finding echo is 2*distance/time........ that means you divide the distance you found which was 132 by 2.... giving 66.......

 

[igs_beast]

oh shi2 thnque