Tap X can fill a bath in 12 minutes. Tap Y can fill a bath in 6 minutes.
How long will it take to fill the bath with both taps running at the same time?

Explanation:

Let's say that this tub is 72 gallons. I picked this number since 12*6 = 72. You can pick any number you want, but I picked this number so we end up with whole number results as shown below.

Tap X can fill the 72 gallon tub in 12 minutes. Its rate is 72/12 = 6 gallons per minute. Tap Y has a rate of 12 gallons per minute because 72/6 = 12.

Add the two unit rates: 6+12 = 18

If the two taps are opened at the same time, then they will work at a rate of 18 gallons per minute.

Let x be the number of minutes. The expression 18x represents how much of the tub is full after x minutes. Set this equal to the 72 we started with earlier and solve for x.

18x = 72

x = 72/18

x = 4

It will take 4 minutes if both taps are running at the same time.

answer:   the paragraph proof is mentioned below.

step-by-step explanation:

given: in a δxwy where

such that, ∠wzx ≅ ∠yzx and zw≅zy

we have to prove that: segment zx is a perpendicular bisector of segment wy.

prove: since, zw≅zy ⇒ ∠wzy is a supplementary angle.

then, ∠wzy= 180°

⇒∠wzx + ∠yzx = 180° ( because xz divides ∠wzy into two parts)

but, ∠wzx ≅ ∠yzx ( given)

⇒∠wzy+∠wzy=180° ( by substitution)

⇒2∠wzy=180°

⇒∠wzy=90°

⇒∠wzy=∠yzx =90°

therefore, xz⊥wy where wz=zy

⇒zx is a perpendicular bisector of wy.