Answer:
rate boat = 15 mph
rate current = 5 mph
explanation:
d = r * t
t = d/r
240 / (r_boat + current) = 12 Multiply both sides by r_boat + r_current.
240 = 12(r_boat + current)
240/ (r_boat - current) = 24 Multiply both sides by r_boat - r_current
240 = 24*(r_boat - current)
Since the distances are the same in both equations, you can equate the right side of each.
12 (r_boat + current) = 24(r_boat - current) Divide by 12
r_boat + current = 2 (r_boat - current) Remove the brackets.
r_boat + current = 2*r_boat - 2* current add 2 currents to both sides
r_boat + 3currents = 2*r_boat Subtract r_boat both sides
3 currents = r_boat.
240 = 12*(r_boat + current. Divide by 12
20 = r_boat + current Put 3 currents in for r_boat
20 = 3currents + 1 current Combine
20 = 4 currents Divide by 4
5 = current
The rate of the current = 5 miles / hour
3 currents = r_boat
3*5 = rate_boat
15 = rate of the boat
Answer:
900
Step-by-step explanation:
multiply 2x2x3x3x5x5
4x9x25 which is 900
Answer:
2
Step-by-step explanation:
1,3,4 are arithmetic sequences
2 is a geometric sequence
Answer:
The angles in the triangle and 10, 80 and 90
Step-by-step explanation:
The two angles that are left in a right triangle add to 90 degrees
8:1 means that there total is 9
8x+1x = 9x
9x = 90
Divide by 9
9x/9 = 90/9
x = 10
8*10 = 80
1*10 = 10
The angles are 80 and 10
The angles in the triangle and 10, 80 and 90
Answer:
Step-by-step explanation:
We can calculate this confidence interval using the population proportion calculation. To do this we must find p' and q'
Where p' = 14/100= 0.14 (no of left handed sample promotion)
q' = 1-p' = 1-0.14= 0.86
Since the requested confidence level is CL = 0.98, then α = 1 – CL = 1 – 0.98 = 0.02/2= 0.01, z (0.01) = 2.326
Using p' - z alpha √(p'q'/n) for the lower interval - 0.14-2.326√(0.14*0.86/100)
= -2.186√0.00325
= -2.186*0.057
= 12.46%
Using p' + z alpha √(p'q'/n)
0.14+2.326√(0.14*0.86/100)
= 0.466*0.057
= 26.5%
Thus we estimate with 98% confidence that between 12% and 27% of all Americans are left handed.
