Answer:
35 minutes
Step-by-step explanation:
The total amount of water is 200 +60 = 260 gallons. The two tanks will have equal amounts when each has half that, or 130 gallons.
If the volume in tank 2 is increasing at 2 gallons per minute, it will increase by 70 gallons from 60 gallons to 130 gallons in 70/2 = 35 minutes.
Cos²(x) + sin²(x)
¹/₂[1 - cos(2x)] + ¹/₂[1 + cos(2x)]
[¹/₂ - ¹/₂cos(2x)] + [¹/₂ + ¹/₂cos(2x)]
¹/₂ + ¹/₂ - ¹/₂cos(2x) + ¹/₂cos(2x)
1