Simplify: (–7) • (8) – (4) • (–2) A. 58 B.16 C.–30 D.–48
1 answer:
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Answer:
The speed of the boat is 5 miles per hours
The speed of the current is 2 miles per hours .
Step-by-step explanation:
Given as :
The distance cover by boat downstream = D = 10.5 miles
The time taken by boat to cover D distance = T = 1.5 hours
The distance cover by boat Upstream = d = 10.5 miles
The time taken by boat to cover d distance = t = 3.5 hours
Let The speed of boat = x mph
Let The speed of current = mph
Now, According to question
∵ Speed =
<u>For Downstream</u>
x + y =
Or, x + y =
Or, x + y = 7 .......A
<u>For Upstream</u>
x - y =
Or, x - y =
Or, x - y = 3 .......B
Now, Solving eq A and eq B
So, (x + y) + (x - y) = 7 + 3
Or, (x + x) + (y - y) = 10
Or, 2 x + 0 = 10
∴ x =
i.e x = 5 mph
So, The speed of the boat = x = 5 miles per hours
Put the value of x into eq A
∵ x + y = 7
Or, 5 + y = 7
∴ y = 7 - 5
i.e y = 2 mph
So, The speed of the current = y = 2 miles per hours
Hence, The speed of the boat is 5 miles per hours and The speed of the current is 2 miles per hours . Answer