Answer:
may be 11.6 but I am not sure
Step-by-step explanation:
let's label each pump A, B, and C, just for convenience. A fills the tank by 1/50 every minute, B fills the tank by 1/60 every minute, and C drains it by 1/75 every minute. Now we can put them all into one function: t(1/50 + 1/60 - 1/75) = 1, where t = our time in minutes and 1 = the tank being full.
next, we solve for t: t = 300/7 minutes, or approximately 42.86 minutes.
Let the speed of plane in still air be x and that wind be y
therefore:
x+y=490
x-y=390
next we solve for the values of x and y, first we add the above equations. This will give us:
2x=880
x=880/2
x=440 miles per hour.
substituting the value of x in one of the equations and solving for y we get:
440+y=490
y=490-440
y=50 miles per hour
The answer would be 0,0 because the dotted line is a negative slope to the right, intersecting the y axis at 2 and the shading is below.
