Answer:
10 kph
Step-by-step explanation:
Find the speed of the current of the river.
20/(20 - c) + 180/(20 + c) = 8
20(20 + c) + 180(20 - c) = 8(400 - c^2)
8c^2 - 160c + 800 = 0
8(c^2 - 20c + 100) = 0
8(c - 10)^2 = 0
c = 10
The speed of the current of the river is 10 km/hour.
Answer:
a) 910
b) 828100
c) 144320
Step-by-step explanation:
a. ∑y
This is the sum of all values of y. So

b. (∑y)^2
This is the square of the sum, so the square of 910, that we found in the previous item.
910² = 828100
c. ∑y^2
This is the sum of the squares of each amount spent. So

Multiply the numbers being added then add the first number. 4X1=4, 4+1=5.
2X5=10, 10+2=12. 11X8=88, 88+8=96. I'm not sure how to get 40, though.
Hope I could help.
Answer:
yea ur correct
Step-by-step explanation:
use PhotoMath or something like that to check next time, it'll save a lot of time
The answer is $10 because 123=$6 and 4 hours is =$4 6+4=10