Teachers plz "Need help " echo

[love-tree]

Person stood between two mountains he hear two echo the first after 2 second, and the second after 2 second from the first echo
Calculate the distance between two mountains when velocity of sound in air equal 340m/s

[خالد ابو بكر المظالى]

زمن الصدى الاول ز1 = 2 ث
زمن الصدى الثانى ز2 = 2+2 4 ثوانى
ف1 =ع× ز1 /2 = 340 ×2 / 2 = 340 م
ف2 = ع ×ز2 /2 = 340 ×4 / 2 = 680 م
ف=ف1 + ف 2 = 340 + 680 = 1020 م

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