Based on the calculations, the speed of this current is equal to 8 miles per hour.
Speed can be defined as the distance covered by an object per unit of time. This ultimately implies that, speed can be measured in miles per hour (mph).
Mathematically, speed can be calculated by using this formula;
Speed = distance/time
Let c represent the speed of the current. Thus, the downstream and upstream speed relative to land would be given by this mathematical expression:
Speed downstream = 11 + c.
Speed upstream = 11 - c.
Also, the total would be given by:
Total time = total distance/speed
Time upstream + time downstream = 22 hours
57/(11 - c) + 57/(11 + c) = 22
Multiplying by (11 - c)(11 + c), we have:
57(11 + c) + 57(11 - c) = 22(11 - c)(11 + c)
57c + 627 + 627 - 57c = 22(121 - c²)
1,254 = 2,662 - 22c²
22c² = 2,662 - 1,254
22c² = 1,408
c² = 1,408/22
c² = 64
c -= √64
c = 8 miles per hour.
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