Atax cut aggregate demand and a. decreases; shifts the ad curve leftward b. decreases; shifts the ad curve rightward c. does not change; does not shift the ad curve d. increases; shifts the ad curve leftward e. increases; shifts the ad curve rightward

E. increases; shifts the AD curve rightward

Step-by-step explanation:

Tax cut means lower tax income tax rates, that mean individuals will have more of their income, that is more money to spend leading to increase in aggregate demand. This will lead to a rise (increase) in the aggregate demand curve which implies rightward movement.

Let x and y be the unit rates at which one large pump and one small pump works, respectively.

Two large/one small operate at a unit rate of

(1 pool)/(4 hours) = 0.25 pool/hour

so that

2x + y = 0.25

One large/three small operate at the same rate,

(1 pool)/(4 hours) = 0.25 pool/hour

x + 3y = 0.25

Solve for x and y. We have

y = 0.25 - 2x   ==>   x + 3 (0.25 - 2x) = 0.25

==>   x + 0.75 - 6x = 0.25

==>   5x = 0.5

==>   x = 0.1

==>   y = 0.25 - 2 (0.1) = 0.25 - 0.2 = 0.05

In other words, one large pump alone can fill a 1/10 of a pool in one hour, while one small pump alone can fill 1/20 of a pool in one hour.

Now, if you have four each of the large and small pumps, they will work at a rate of

4x + 4y = 4 (0.1) + 4 (0.05) = 0.6

meaning they can fill 3/5 of a pool in one hour. If it takes time t to fill one pool, we have

(3/5 pool/hour) (t hours) = 1 pool

==>   t = (1 pool) / (3/5 pool/hour) = 5/3 hours

So it would take 5/3 hours, or 100 minutes, for this arrangement of pumps to fill one pool.